Niels C Rattenborg
Full Text Available Twice a year, normally diurnal songbirds engage in long-distance nocturnal migrations between their wintering and breeding grounds. If and how songbirds sleep during these periods of increased activity has remained a mystery. We used a combination of electrophysiological recording and neurobehavioral testing to characterize seasonal changes in sleep and cognition in captive white-crowned sparrows (Zonotrichia leucophrys gambelii across nonmigratory and migratory seasons. Compared to sparrows in a nonmigratory state, migratory sparrows spent approximately two-thirds less time sleeping. Despite reducing sleep during migration, accuracy and responding on a repeated-acquisition task remained at a high level in sparrows in a migratory state. This resistance to sleep loss during the prolonged migratory season is in direct contrast to the decline in accuracy and responding observed following as little as one night of experimenter-induced sleep restriction in the same birds during the nonmigratory season. Our results suggest that despite being adversely affected by sleep loss during the nonmigratory season, songbirds exhibit an unprecedented capacity to reduce sleep during migration for long periods of time without associated deficits in cognitive function. Understanding the mechanisms that mediate migratory sleeplessness may provide insights into the etiology of changes in sleep and behavior in seasonal mood disorders, as well as into the functions of sleep itself.
Full Text Available Abstract Background Sleep is regulated by both a circadian and a homeostatic process. The homeostatic process reflects the duration of prior wakefulness: the longer one stays awake, the longer and/or more intense is subsequent sleep. In mammals, the best marker of the homeostatic sleep drive is slow wave activity (SWA, the electroencephalographic (EEG power spectrum in the 0.5–4 Hz frequency range during non-rapid eye movement (NREM sleep. In mammals, NREM sleep SWA is high at sleep onset, when sleep pressure is high, and decreases progressively to reach low levels in late sleep. Moreover, SWA increases further with sleep deprivation, when sleep also becomes less fragmented (the duration of sleep episodes increases, and the number of brief awakenings decreases. Although avian and mammalian sleep share several features, the evidence of a clear homeostatic response to sleep loss has been conflicting in the few avian species studied so far. The aim of the current study was therefore to ascertain whether established markers of sleep homeostasis in mammals are also present in the white-crowned sparrow (Zonotrichia leucophrys gambelii, a migratory songbird of the order Passeriformes. To accomplish this goal, we investigated amount of sleep, sleep time course, and measures of sleep intensity in 6 birds during baseline sleep and during recovery sleep following 6 hours of sleep deprivation. Results Continuous (24 hours EEG and video recordings were used to measure baseline sleep and recovery sleep following short-term sleep deprivation. Sleep stages were scored visually based on 4-sec epochs. EEG power spectra (0.5–25 Hz were calculated on consecutive 4-sec epochs. Four vigilance states were reliably distinguished based on behavior, visual inspection of the EEG, and spectral EEG analysis: Wakefulness (W, Drowsiness (D, slow wave sleep (SWS and rapid-eye movement (REM sleep. During baseline, SWA during D, SWS, and NREM sleep (defined as D and SWS
Meddle, Simone L; Romero, L Michael; Astheimer, Lee B; Buttemer, William A; Moore, Ignacio T; Wingfield, John C
The breeding season is very brief for arctic-breeding passerines, and any interruptions of parental care by aggressive interactions over territory may reduce reproductive success. We tested both the "testosterone insensitivity" and "corticosterone insensitivity" hypotheses in the arctic-breeding Gambel's white-crowned sparrow, Zonotrichia leucophrys gambelii. Additionally, we tested whether simulated territorial intrusions (STIs), known to stimulate increases in luteinizing hormone (LH) and testosterone (T) in mid-latitude breeding Z. l. pugetensis, would also be effective in either the early or late phases of the brief breeding season of Z. l. gambelii. Plasma levels of T and LH were high early in the breeding season and declined as egg laying began. Exposure of free-living males to 10 min of STI significantly increased LH but not T secretion. Nonetheless, the pituitary-gonadal axis is sensitive as jugular injection of gonadotrophin-releasing hormone increased plasma T at 10 min relative to saline-challenged controls. T implants failed to increase territorial aggression following STI during incubation. These data are consistent with the T insensitivity hypothesis and contrast sharply with the response of the southerly breeding subspecies, Z. l. pugetensis, in which the territorial response to T administration is retained throughout its relatively long breeding season. However, corticosterone implants during the incubation period decreased territorial aggression during STI. This responsiveness to corticosterone is not consistent with the corticosterone insensitivity hypothesis of stress modulation. Z. l. gambelii retain sensitivity to corticosterone levels that may occur naturally in response to environmental perturbations resulting in suppression of territorial behavior.
Welch, Kenneth C.; Ramenofsky, Marilyn
Birds undergo numerous changes as they progress through life-history stages, yet relatively few studies have examined how birds adapt to both the dynamic energetic and mechanical demands associated with such transitions. Myosin heavy chain (MyHC) expression, often linked with muscle fibre type, is strongly correlated with a muscle's mechanical power-generating capability, thus we examined several morphological properties, including MyHC expression of the pectoralis, in a long-distance migrant, the white-crowned sparrow (Zonotrichia leucophrys gambelii) throughout the progression from winter, spring departure and arrival on breeding grounds. White-crowned sparrows demonstrated significant phenotypic flexibility throughout the seasonal transition, including changes in prealternate moult status, lipid fuelling, body condition and flight muscle morphology. Pectoral MyHC expression also varied significantly over the course of the study. Wintering birds expressed a single, newly classified adult fast 2 isoform. At spring departure, pectoral isoform expression included two MyHC isoforms: the adult fast 2 isoform along with a smaller proportion of a newly present adult fast 1 isoform. By spring arrival, both adult fast isoforms present at departure remained, yet expression had shifted to a greater relative proportion of the adult fast 1 isoform. Altering pectoral MyHC isoform expression in preparation for and during spring migration may represent an adaptation to modulate muscle mechanical output to support long-distance flight. PMID:28018664
Gang WANG; Marilyn RAMENOFSKY; John C.WINGFIELD
In seasonally breeding birds,the annual cycle of photoperiod is a principal environmental cue for temporal arrangement of different life-history stages,such as migration and breeding.In the past,most research has focused on the mechanisms of photoperiodic control of breeding with less attention paid to migration.In Gambel's white-crowned sparrow Zonotrichia leucophrys gambelii (GWCS),photoreceptors for induction of breeding are known to reside in the basal hypothalamus.However,it is unknown whether the sites of photoperiodic reception for vernal migration are the same as those for breeding.Therefore,we hypothesized that they may be controlled separately.In this study,we exposed photosensitive GWCSs to low-penetration green light (wavelength at 510 rm) under a regime of 1 lux during the day and ＜0.1 lux at night,and switched the photoperiodic conditions from short day (10 h daytime) to long day (18 h daytime).The results showed that the experimental birds developed traits associated with vernal migration including mass increase,fat deposition and migratory restlessness behavior when transferred from short day to long day green light cycles,while control birds maintained continuously on short day green light conditions did not express any migration related characteristics.Neither experimental nor control groups showed gonadal recrudescence under either green light cycles.In support of our hypothesis,we were able to apparently dissociate the photoperiodic responses regulating vernal migration and breeding,which suggests separate mechanisms ofphotoperiodic time measurement.Such distinct photoperiodic mechanisms may drive the fine-tuned temporal arrangement of the two life history stages.
The Effects of Acute Restraint Stress on Plasma Levels of Prolactin and Corticosterone across Life-History Stages in a Short-Lived Bird: Gambel's White-Crowned Sparrow (Zonotrichia leucophrys gambelii).
Krause, Jesse S; Meddle, Simone L; Wingfield, John C
The general reproductive effort model attempts to predict the resources that will be allocated to a current reproductive bout or to future survival by aborting the current reproductive attempt. Life-history theory predicts that short-lived species should devote more resources toward a reproductive event because brood value is far greater compared with that of long-lived species that have multiple breeding opportunities. Previous bird studies have used patterns of hormone secretion to understand the regulation of parental investment in response to environmental challenges, such as stress. The two key hormones investigated have been prolactin, which promotes parental investment, and corticosterone, which can reduce parental investment. Research on long-lived seabirds showed that prolactin levels decrease in response to a stressor, but the magnitude of the decline was positively correlated with future reproductive potential. However, little is known about the role of prolactin in short-lived species. Here we present prolactin and corticosterone data from a short-lived Arctic breeding, migratory songbird-the white-crowned sparrow, Zonotrichia leucophrys gambelii-at multiple stages of the breeding and nonbreeding seasons following standardized acute restraint stress. These data show that both prolactin and corticosterone are modulated seasonally. Corticosterone levels increased significantly in response to acute restraint stress during the breeding season in both sexes, but prolactin levels did not change in response to acute restraint stress at any stage of the annual cycle. We found no relationship between corticosterone or prolactin at either baseline or peak induced levels during any stage of breeding.
Virginia, United States; www.dragonflyinc.com). The cable was attached to the bird’s cranium using dental acrylic (Justi Products, Oxnard, California...aspects of the project: Brian Asti, Monique Duwell, Jennifer Fahy, Gretchen Fredericks, Bridgette Harder, Stephany Jones, Dolores Martinez-Gonzalez
Hannan Ciaran T
Full Text Available Abstract Background We have previously shown that the White-crowned Sparrow (WCS decreases sleep by 60% during a period of migratory restlessness relative to a non-migratory period when housed in a 12 h light: 12 h dark cycle. Despite this sleep reduction, accuracy of operant performance was not impaired, and in fact rates of responding were elevated during the migratory period, effects opposite to those routinely observed following enforced sleep deprivation. To determine whether the previously observed increases in operant responding were due to improved performance or to the effects of migration on activity level, here we assessed operant performance using a task in which optimal performance depends on the bird's ability to withhold a response for a fixed interval of time (differential-reinforcement-of-low-rate-behavior, or DRL; elevated response rates ultimately impair performance by decreasing access to food reward. To determine the influence of seasonal changes in day length on sleep and behavioral patterns, we recorded sleep and assessed operant performance across 4 distinct seasons (winter, spring, summer and fall under a changing photoperiod. Results Sleep amount changed in response to photoperiod in winter and summer, with longest sleep duration in the winter. Sleep duration in the spring and fall migratory periods were similar to what we previously reported, and were comparable to sleep duration observed in summer. The most striking difference in sleep during the migratory periods compared to non-migratory periods was the change from discrete day-night temporal organization to an almost complete temporal fragmentation of sleep. The birds' ability to perform on the DRL task was significantly impaired during both migratory periods, but optimal performance was sustained during the two non-migratory periods. Conclusions Birds showed dramatic changes in sleep duration across seasons, related to day length and migratory status. Migration was associated with changes in sleep amount and diurnal distribution pattern, whereas duration of sleep in the non-migratory periods was largely influenced by the light-dark cycle. Elevated response rates on the DRL task were observed during migration but not during the short sleep duration of summer, suggesting that the migratory periods may be associated with decreased inhibition/increased impulsivity. Although their daily sleep amounts and patterns may vary by season, birds are susceptible to sleep loss throughout the year, as evidenced by decreased responding rates following enforced sleep deprivation.
Vyas, N.B.; Kuenzel, W.J.; Hill, E.F.; Sauer, J.R.
Migratory white-throated sparrows (Zonotrichia albicollis) were exposed to acephate (acetylphosphoramidothioic acid O,S-dimethyl ester), an organophosphorus pesticide, to determine its effects on migratory orientation and behavior. Birds were also exposed to polarizer sheets to determine the mechanism by which acephate may affect migratory orientation. Adult birds exposed to 256 ppm acephate a.i. were not able to establish a preferred migratory orientation and exhibited random activity. All juvenile treatment groups displayed a seasonally correct southward migratory orientation. We hypothesize that acephate may have produced aberrant migratory behavior by affecting the memory of the migratory route and wintering ground. This experiment reveals that an environmentally relevant concentration of a common organophosphorus pesticide can alter migratory orientation, but its effect is markedly different between adult and juvenile sparrows. Results suggest that the survival of free-flying adult passerine migrants may be compromised following organophosphorus pesticide exposure.
Lougheed, Stephen C; Campagna, Leonardo; Dávila, José A; Tubaro, Pablo L; Lijtmaer, Darío A; Handford, Paul
The Neotropics are exceptionally diverse, containing roughly one third of all extant bird species on Earth. This remarkable species richness is thought to be a consequence of processes associated with both Andean orogenesis throughout the Tertiary, and climatic fluctuations during the Quaternary. Phylogeographic studies allow insights into how such events might have influenced evolutionary trajectories of species and ultimately contribute to a better understanding of speciation. Studies on continentally distributed species are of particular interest because different populations of such taxa may show genetic signatures of events that impacted the continent-wide biota. Here we evaluate the genealogical history of one of the world's most broadly-distributed and polytypic passerines, the rufous-collared sparrow (Zonotrichia capensis). We obtained control region DNA sequences from 92 Zonotrichia capensis individuals sampled across the species' range (Central and South America). Six additional molecular markers, both nuclear and mitochondrial, were sequenced for a subset of individuals with divergent control region haplotypes. Median-joining network analysis, and Bayesian and maximum parsimony phylogenetic analyses all recovered three lineages: one spanning Middle America, the Dominican Republic, and north-western South America; one encompassing the Dominican Republic, Roraima (Venezuela) and La Paz (Bolivia) south to Tierra del Fuego, Argentina; and a third, including eastern Argentina and Brazil. Phylogenetic analyses suggest that the Middle American/north-western South American clade is sister to the remaining two. Bayesian and maximum likelihood coalescent simulations used to study lineage demographic history, diversification times, migration rates and population expansion together suggested that diversification of the three lineages occurred rapidly during the Pleistocene, with negligible gene flow, leaving genetic signatures of population expansions. The
Lynn, Sharon E; Prince, Leslie E; Schook, Derek M; Moore, Ignacio T
In most male birds that exhibit paternal care, elevation in testosterone above the breeding baseline reduces nestling provisioning, which can be detrimental to offspring survival. Mechanisms that may allow some males to avoid this detrimental effect of elevated testosterone include (1) decreased sensitivity to testosterone's effects on behavior and (2) uncoupling of testosterone secretion from territorial challenges (thus reducing the number of transient elevations in testosterone above the breeding baseline). Both of these "cost-avoidance" mechanisms have been documented, but whether selection for these mechanisms is correlated or independent is unknown. We investigated the relationship between elevated testosterone and paternal care in a tropical bird, the rufous-collared sparrow (Zonotrichia capensis). Zonotrichia capensis males exhibit an uncoupling of testosterone secretion from territorial aggression, and this species has a flexible breeding season and a clutch size smaller than those of temperate congeners. We implanted males with testosterone or empty implants and observed paternal behavior 2-3 and 6-7 d posthatch. During both observation periods, 100% of control males fed chicks, whereas 22% and 0% of testosterone-implanted males fed chicks on days 2-3 and 6-7, respectively. Chicks of testosterone-implanted males weighed less than control chicks, but tarsus growth, wing growth, and fledging success did not differ. Thus, we demonstrate a robust negative effect of testosterone on nestling provisioning that may not ultimately affect reproductive success. We suggest that these results relate to extreme flexibility in breeding schedule and the small clutch size in this tropical species. Our data also suggest that selection for the two mechanisms to avoid deleterious effects of elevations in testosterone above the breeding baseline likely occurs independently.
Addis, Elizabeth A; Clark, Aaron D; Vasquez, Rodrigo A; Wingfield, John C
The roles of testosterone (T) during reproduction are often complex and vary among and within vertebrate taxa and locations, making general hypotheses relating T to breeding behavior and success difficult to integrate. In birds, T is thought to influence degrees of territoriality and associated aggression in males to maximize breeding success. Importantly, most work supporting these ideas has been conducted in the Northern Hemisphere. However, accumulating work on tropical species has shown divergent patterns of T in association with breeding behavior. The compilation of work from northern temperate and tropical species suggests that the function of T in relation to breeding behavior varies across latitude and environmental conditions. We investigate the patterns of T in relation to breeding behavior in a subspecies of the rufous-collared sparrow Zonotrichia capensis australis breeding at high latitude in the Southern Hemisphere (55°S). We then compare the T profiles and breeding behaviors of male Z. c. australis to conspecifics breeding in the tropics and congeners in North America to test the hypothesis that environments with breeding seasons of similar lengths will drive similar patterns of T in relation to breeding behavior. We found that Z. c. australis have high levels of T during the early-breeding periods when territories are being established and low levels of T during the parental phase of breeding, similar to temperate and Arctic birds in the Northern Hemisphere but unlike tropical Zonotrichia capensis costaricensis. In contrast, we found that Z. c. australis also exhibit similar aggressive behaviors in early breeding and midbreeding, unlike many birds in the Northern Hemisphere.
Osmoregulatory responses to dietary protein and water intake in the granivorous Zonotrichia capensis (Passerine, Emberizidae Respuestas osmorregulatorias a la proteína dietaria y al consumo de agua en el granívoro Zonotrichia capensis (Paseriformes, Emberizidae
Full Text Available We studied the osmoregulatory responses of the granivore Zonotrichia capensis, acclimated to high- and low-protein diets as well as two levels of water intake. We tested whether Z. capensis has the ability to modify the proportion of nitrogenous waste in the excreta when protein intake and water intake varies. After 21 days of acclimation, plasma osmolality was not significantly affected by dietary treatment; however, excreta osmolality was higher in the high-protein group compared to the low-protein group. Nitrogenous wastes in Z. capensis are excreted mainly in the form of uric acid. The proportion of kidney devoted to medullary tissue was 40 % higher in dehydrated birds than in hydrated birds. Excreta osmolality was higher in dehydrated birds, and in all cases higher than plasma concentration by more than 300 mOsm kg"¹. Our data do not support the hypothesis that Z. capensis can switch nitrogen excretion pathways. We hypothesize that the low water content of the seed-base diet, the comparatively low water intake, and the large difference between urine and plasma concentrations may minimize the retrograde flux of urine to the lower intestinal tract, thereby reducing the potential for post-renal urine modificationEstudiamos la respuesta osmorregulatoria del granívoro Zonotrichia capensis, aclimatado a dietas con alta y baja proteína como también a dos niveles de ingestión de agua. Evaluamos si Z. capensis tiene la capacidad de modificar la proporción de los desechos nitrogenados en la excreta cuando la ingestión de proteína y agua varía. Después de 21 días de aclimatación, la osmolalidad del plasma no fue afectada significativamente por el tratamiento dietario. Sin embargo, la osmolalidad de la excreta fue mayor en el grupo alta-proteína comparado con el grupo baja-proteína. Los desechos nitrogenados en Z. capensis son excretados mayoritariamente en forma de ácido úrico. La proporción del riñon ocupado por tejido medular fue
Lorena Tellez-Farfán; Francisco Alejnadro Sánchez
El copetón Zonotrichia capensis tiene una amplia distribución en América neotropical, es un ave tolerante a las intervenciones humanas, pero sabemos poco sobre su comportamiento de forrajeo en los Andes colombianos. Por ello, estudiamos la estrategia de forrajeo del copetón y, adicionalmente, el valor de parches alimentarios a lo largo de dos cercas vivas jóvenes (plantación < 2 años), en relación con la distancia a una zona de ronda del río Bogotá, en Cajicá, Sabana de Bogotá, Colombia. E...
Caras, Melissa L; Brenowitz, Eliot; Rubel, Edwin W
Song in oscine birds is a learned behavior that plays important roles in breeding. Pronounced seasonal differences in song behavior and in the morphology and physiology of the neural circuit underlying song production are well documented in many songbird species. Androgenic and estrogenic hormones largely mediate these seasonal changes. Although much work has focused on the hormonal mechanisms underlying seasonal plasticity in songbird vocal production, relatively less work has investigated seasonal and hormonal effects on songbird auditory processing, particularly at a peripheral level. We addressed this issue in Gambel's white-crowned sparrow (Zonotrichia leucophrys gambelii), a highly seasonal breeder. Photoperiod and hormone levels were manipulated in the laboratory to simulate natural breeding and non-breeding conditions. Peripheral auditory function was assessed by measuring the auditory brainstem response (ABR) and distortion product otoacoustic emissions (DPOAEs) of males and females in both conditions. Birds exposed to breeding-like conditions demonstrated elevated thresholds and prolonged peak latencies when compared with birds housed under non-breeding-like conditions. There were no changes in DPOAEs, however, which indicates that the seasonal differences in ABRs do not arise from changes in hair cell function. These results suggest that seasons and hormones impact auditory processing as well as vocal production in wild songbirds.
Caras, Melissa L; O'Brien, Matthew; Brenowitz, Eliot A; Rubel, Edwin W
Sex steroids modulate vertebrate sensory processing, but the impact of circulating hormone levels on forebrain function remains unclear. We tested the hypothesis that circulating sex steroids modulate single-unit responses in the avian telencephalic auditory nucleus, field L. We mimicked breeding or nonbreeding conditions by manipulating plasma 17β-estradiol levels in wild-caught female Gambel's white-crowned sparrows (Zonotrichia leucophrys gambelii). Extracellular responses of single neurons to tones and conspecific songs presented over a range of intensities revealed that estradiol selectively enhanced auditory function in cells that exhibited monotonic rate level functions to pure tones. In these cells, estradiol treatment increased spontaneous and maximum evoked firing rates, increased pure tone response strengths and sensitivity, and expanded the range of intensities over which conspecific song stimuli elicited significant responses. Estradiol did not significantly alter the sensitivity or dynamic ranges of cells that exhibited non-monotonic rate level functions. Notably, there was a robust correlation between plasma estradiol concentrations in individual birds and physiological response properties in monotonic, but not non-monotonic neurons. These findings demonstrate that functionally distinct classes of anatomically overlapping forebrain neurons are differentially regulated by sex steroid hormones in a dose-dependent manner.
Tsahar, Ella; Arad, Zeev; Izhaki, Ido; Guglielmo, Christopher G
Uric acid is the main nitrogenous waste product in birds but it is also known to be a potent antioxidant. Hominoid primates and birds lack the enzyme urate oxidase, which oxidizes uric acid to allantoin. Consequently, the presence of allantoin in their plasma results from non-enzymatic oxidation. In humans, the allantoin to uric acid ratio in plasma increases during oxidative stress, thus this ratio has been suggested to be an in vivo marker for oxidative stress in humans. We measured the concentrations of uric acid and allantoin in the plasma and ureteral urine of white-crowned sparrows (Zonotrichia leucophrys gambelii) at rest, immediately after 30 min of exercise in a hop/hover wheel, and after 1 h of recovery. The plasma allantoin concentration and the allantoin to uric acid ratio did not increase during exercise but we found a positive relationship between the concentrations of uric acid and allantoin in the plasma and in the ureteral urine in the three activity phases. In the plasma, the slope of the regression describing the above positive relationships was significantly higher immediately after activity. We suggest that the slope indicates the rate of uric acid oxidation and that during activity this rate increases as a result of higher production of free radicals. The present study demonstrates that allantoin is present in the plasma and in the ureteral urine of white-crowned sparrows and therefore might be useful as an indicator of oxidative stress in birds.
Full Text Available El copetón Zonotrichia capensis tiene una amplia distribución en América neotropical, es un ave tolerante a las intervenciones humanas, pero sabemos poco sobre su comportamiento de forrajeo en los Andes colombianos. Por ello, estudiamos la estrategia de forrajeo del copetón y, adicionalmente, el valor de parches alimentarios a lo largo de dos cercas vivas jóvenes (plantación < 2 años, en relación con la distancia a una zona de ronda del río Bogotá, en Cajicá, Sabana de Bogotá, Colombia. El río es un área dominada por árboles en una matriz rural a urbana. Utilizamos parches artificiales hechos de bandejas de aluminio con semillas mezcladas con arena. Determinamos la proporción de consumo entre tres parches con diferentes densidades de alimento inicial, para determinar si los copetones obtienen información del parche. Usamos también parches artificiales para determinar si la distancia al río a lo largo de dos cercas vivas jóvenes afectaba el forrajeo. Nuestros resultados indican que Z. capensis no obtuvo información del parche y no reconoció diferencias en parches con diferente densidad inicial de alimento. Adicionalmente, la distancia al río afectó el valor de los parches de forrajeo en solo una de las cercas vivas examinadas donde hubo mayor consumo cerca al río. Al parecer, la densidad inicial de alimento no afectó el nivel de explotación del parche por parte de los copetones, mientras que el valor del parche en las cercas vivas jóvenes puede estar influido por la distancia al río.Foraging Behavior of Zonotrichia capensis (Passeriformes: Emberizidae and Patch Value in Young Live Fences in the Bogotá High PlateauThe Rufous-collared Sparrow Zonotrichia capensis is a widely distributed species in neotropical America, it is tolerant to human interventions, but we know little about its foraging ecology on the Colombian Andes. Therefore, we studied the foraging strategy and, additionally, the value of foraging patches
Cheviron, Zachary A; Natarajan, Chandrasekhar; Projecto-Garcia, Joana; Eddy, Douglas K; Jones, Jennifer; Carling, Matthew D; Witt, Christopher C; Moriyama, Hideaki; Weber, Roy E; Fago, Angela; Storz, Jay F
In air-breathing vertebrates, the physiologically optimal blood-O2 affinity is jointly determined by the prevailing partial pressure of atmospheric O2, the efficacy of pulmonary O2 transfer, and internal metabolic demands. Consequently, genetic variation in the oxygenation properties of hemoglobin (Hb) may be subject to spatially varying selection in species with broad elevational distributions. Here we report the results of a combined functional and evolutionary analysis of Hb polymorphism in the rufous-collared sparrow (Zonotrichia capensis), a species that is continuously distributed across a steep elevational gradient on the Pacific slope of the Peruvian Andes. We integrated a population genomic analysis that included all postnatally expressed Hb genes with functional studies of naturally occurring Hb variants, as well as recombinant Hb (rHb) mutants that were engineered through site-directed mutagenesis. We identified three clinally varying amino acid polymorphisms: Two in the α(A)-globin gene, which encodes the α-chain subunits of the major HbA isoform, and one in the α(D)-globin gene, which encodes the α-chain subunits of the minor HbD isoform. We then constructed and experimentally tested single- and double-mutant rHbs representing each of the alternative α(A)-globin genotypes that predominate at different elevations. Although the locus-specific patterns of altitudinal differentiation suggested a history of spatially varying selection acting on Hb polymorphism, the experimental tests demonstrated that the observed amino acid mutations have no discernible effect on respiratory properties of the HbA or HbD isoforms. These results highlight the importance of experimentally validating the hypothesized effects of genetic changes in protein function to avoid the pitfalls of adaptive storytelling. © The Author 2014. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please
Full Text Available El copetón Zonotrichia capensis tiene una amplia distribución en América neotropical, es un ave tolerante a las intervenciones humanas, pero sabemos poco sobre su comportamiento de forrajeo en los Andes colombianos. Por ello, estudiamos la estrategia de forrajeo del copetón y, adicionalmente, el valor de parches alimentarios a lo largo de dos cercas vivas jóvenes (plantación < 2 años, en relación con la distancia a una zona de ronda del río Bogotá, en Cajicá, Sabana de Bogotá, Colombia. El río es un área dominada por árboles en una matriz rural a urbana. Utilizamos parches artificiales hechos de bandejas de aluminio con semillas mezcladas con arena. Determinamos la proporción de consumo entre tres parches con diferentes densidades de alimento inicial, para determinar si los copetones obtienen información del parche. Usamos también parches artificiales para determinar si la distancia al río a lo largo de dos cercas vivas jóvenes afectaba el forrajeo. Nuestros resultados indican que Z. capensis no obtuvo información del parche y no reconoció diferencias en parches con diferente densidad inicial de alimento. Adicionalmente, la distancia al río afectó el valor de los parches de forrajeo en solo una de las cercas vivas examinadas donde hubo mayor consumo cerca al río. Al parecer, la densidad inicial de alimento no afectó el nivel de explotación del parche por parte de los copetones, mientras que el valor del parche en las cercas vivas jóvenes puede estar influido por la distancia al río.
Krause, Jesse S; Chmura, Helen E; Pérez, Jonathan H; Quach, Lisa N; Asmus, Ashley; Word, Karen R; McGuigan, Michaela A; Sweet, Shannan K; Meddle, Simone L; Gough, Laura; Boelman, Natalie; Wingfield, John C
Individuals at the forefront of a range shift are likely to exhibit phenotypic traits that distinguish them from the population breeding within the historic range. Recent studies have examined morphological, physiological and behavioral phenotypes of individuals at the edge of their range. Several studies have found differences in the hypothalamic-pituitary-adrenal (HPA) axis activity in response to acute restraint stress in individuals at the range limits. HPA axis activation leads to elevations in glucocorticoids that regulate physiology and behavior. Here we compare the hormonal profiles and morphometrics from Gambel's white-crowned sparrows (Zonotrichia leucophrys gambelii) breeding at the northern limit of the population's range to those birds breeding within the historic population range. Birds breeding at the northern limit experienced a harsher environment with colder temperatures; however, we found no differences in arthropod prey biomass between the northern limit and more southern (historic) sites. Males at the northern limit had higher body condition scores (mass corrected for body size) compared to individuals within the historic range, but no differences were found in beak and tarsus lengths, wing chord, muscle profile or fat stores. In males during the pre-parental stage, before breeding commenced, HPA axis activity was elevated in birds at the northern limit of the range, but no differences were found during the parental or molt stages. Females showed no differences in HPA axis activity during the parental stage. This study suggests that "pioneering" individuals at the limits of their breeding range exhibit physiology and morphology that are distinct from individuals within the historic range.
Ashley, Noah T; Hays, Quentin R; Bentley, George E; Wingfield, John C
Males of many vertebrate species are typically more prone to disease and infection than female conspecifics, and this sexual difference is partially influenced by the immunosuppressive properties of testosterone (T) in males. T-induced immunosuppression has traditionally been viewed as a pleiotropic handicap, rather than an adaptation. Recently, it has been hypothesized that suppression of sickness behavior, or the symptoms of infection, may have adaptive value if sickness interferes with the expression of T-mediated behaviors important for male reproductive success. We conduct a classic hormone replacement experiment to examine if T suppresses sickness behavior in a seasonally-breeding songbird, Gambel's white-crowned sparrow (Zonotrichia leucophrys gambelii). Triggered experimentally by bacterial lipopolysaccharide (LPS), sickness behavior includes decreased activity, anorexia, and weight loss. Gonadectomized (GDX) males that were treated with silastic implants filled with T exhibited suppression of behavioral and physiological responses to LPS compared to GDX and sham-GDX controls given empty implants. Sickness responses of control groups were statistically indistinguishable. T-implanted birds had significantly higher plasma T than control groups and levels were within the range associated with aggressive interactions during male-to-male contests. These findings imply that suppression of sickness behavior could occur when T is elevated to socially-modulated levels. Alternatively, it is possible that this suppressive effect is mediated through a stress-induced mechanism, as corticosterone levels were elevated in T-implanted subjects compared to controls. We propose that males wounded and infected during contests may gain a brief selective advantage by suppressing sickness responses that would otherwise impair competitive performance. The cost of immunosuppression would be manifested in males through an increased susceptibility to disease, which is presumably
Stevenson, Tyler J; Small, Thomas W; Ball, Gregory F; Moore, Ignacio T
Seasonal breeding in temperate zone vertebrates is characterised by pronounced variation in both central and peripheral reproductive physiology as well as behaviour. In contrast, many tropical species have a comparatively longer and less of a seasonal pattern of breeding than their temperate zone counterparts. These extended, more "flexible" reproductive periods may be associate with a lesser degree of annual variation in reproductive physiology. Here we investigated variation in the neuroendocrine control of reproduction in relation to the changes in the neural song control system in a tropical breeding songbird the rufous-collared sparrows (Zonotrichia capensis). Using in situ hybridization, we show that the optical density of GnRH1 mRNA expression is relatively constant across pre-breeding and breeding states. However, males were found to have significantly greater expression compared to females regardless of breeding state. Both males and females showed marked variation in measures of peripheral reproductive physiology with greater gonadal volumes and concentrations of sex steroids in the blood (i.e. testosterone in males; estrogen in females) during the breeding season as compared to the pre-breeding season. These findings suggest that the environmental cues regulating breeding in a tropical breeding bird ultimately exert their effects on physiology at the level of the median eminence and regulate the release of GnRH1. In addition, histological analysis of the song control system HVC, RA and Area X revealed that breeding males had significantly larger volumes of these brain nuclei as compared to non-breeding males, breeding females, and non-breeding females. Females did not exhibit a significant difference in the size of song control regions across breeding states. Together, these data show a marked sex difference in the extent to which there is breeding-associated variation in reproductive physiology and brain plasticity that is dependent on the reproductive
Tania Macouzet; Patricia Escalante-Pliego
We report here 4 new bird records found among a large-scale compilation of specimen records in museums worldwide, Atlas de las Aves de Mexico. The new records are for 4 migratory species, Empidonax alnorum (Alder Flycatcher), Vireo solitarius (Solitary Vireo), Catharus fuscescens (Veery), and Zonotrichia leucophrys (White-crowned Sparrow). These species are not to-date known from Cozumel, although they are considered transients in the Yucatán Peninsula.Se encontraron 4 nuevos registros de esp...
Tania Macouzet; Patricia Escalante-Pliego
We report here 4 new bird records found among a large-scale compilation of specimen records in museums worldwide, Atlas de las Aves de Mexico. The new records are for 4 migratory species, Empidonax alnorum (Alder Flycatcher), Vireo solitarius (Solitary Vireo), Catharus fuscescens (Veery), and Zonotrichia leucophrys (Whitecrowned Sparrow). These species are not to-date known from Cozumel, although they are considered transients in the Yucatán Peninsula.
Macedo-Lima, Matheus; Miller, Kimberly E.; Brenowitz, Eliot A.
Seasonally breeding songbirds exhibit pronounced annual changes in song behavior, and in the morphology and physiology of the telencephalic neural circuit underlying production of learned song. Each breeding season, new adult-born neurons are added to the pallial nucleus HVC in response to seasonal changes in steroid hormone levels, and send long axonal projections to their target nucleus, the robust nucleus of the arcopallium (RA). We investigated the role that adult neurogenesis plays in the seasonal reconstruction of this circuit. We labeled newborn HVC neurons with BrdU, and RA-projecting HVC neurons (HVCRA) with retrograde tracer injected in RA of adult male white-crowned sparrows (Zonotrichia leucophrys gambelii) in breeding or nonbreeding conditions. We found that there were many more HVCRA neurons in breeding than nonbreeding birds. Furthermore, we observed that more newborn HVC neurons were back-filled by the tracer in breeding animals. Behaviorally, song structure degraded as the HVC-RA circuit degenerated, and recovered as the circuit regenerated, in close correlation with the number of new HVCRA neurons. These results support the hypothesis that the HVC-RA circuit degenerates in nonbreeding birds, and that newborn neurons reconstruct the circuit in breeding birds, leading to functional recovery of song behavior. SIGNIFICANCE STATEMENT We investigated the role that adult neurogenesis plays in the seasonal reconstruction of a telencephalic neural circuit that controls song behavior in white-crowned sparrows. We showed that nonbreeding birds had a 36%–49% reduction in the number of projection neurons compared with breeding birds, and the regeneration of the circuit in the breeding season is due to the integration of adult-born projection neurons. Additionally, song structure degraded as the circuit degenerated and recovered as the circuit regenerated, in close correlation with new projection neuron number. This study demonstrates that steroid hormones
Full Text Available We report here 4 new bird records found among a large-scale compilation of specimen records in museums worldwide, Atlas de las Aves de Mexico. The new records are for 4 migratory species, Empidonax alnorum (Alder Flycatcher, Vireo solitarius (Solitary Vireo, Catharus fuscescens (Veery, and Zonotrichia leucophrys (White-crowned Sparrow. These species are not to-date known from Cozumel, although they are considered transients in the Yucatán Peninsula.Se encontraron 4 nuevos registros de especies de aves para la Isla Cozumel obtenidos a través del análisis de un compendio de registros de ejemplares de aves depositados en los museos del mundo, Atlas de las Aves de México. Las especies encontradas fueron Empidonax alnorum (mosquero ailero, Vireo solitarius (vireo cabeza azul, Catharus fuscescens (zorzal rojizo y Zonotrichia leucophrys (gorrión corona blanca. Para estas especies no se tenían registros en la Isla Cozumel aunque se consideran migratorias "de paso" en el área de la península de Yucatán.
Erica F Stuber
Full Text Available White-throated sparrows increase fat deposits during pre-migratory periods and rely on these fat stores to fuel migration. Adipose tissue produces hormones and signaling factors in a rhythmic fashion and may be controlled by a clock in adipose tissue or driven by a master clock in the brain. The master clock may convey photoperiodic information from the environment to adipose tissue to facilitate pre-migratory fattening, and adipose tissue may, in turn, release adipokines to indicate the extent of fat energy stores. Here, we present evidence that a change in signal from the adipokines adiponectin and visfatin may act to indicate body condition, thereby influencing an individual's decision to commence migratory flight, or to delay until adequate fat stores are acquired. We quantified plasma adiponectin and visfatin levels across the day in captive birds held under constant photoperiod. The circadian profiles of plasma adiponectin in non-migrating birds were approximately inverse the profiles from migrating birds. Adiponectin levels were positively correlated to body fat, and body fat was inversely related to the appearance of nocturnal migratory restlessness. Visfatin levels were constant across the day and did not correlate with fat deposits; however, a reduction in plasma visfatin concentration occurred during the migratory period. The data suggest that a significant change in the biological control of adipokine expression exists between the two migratory conditions and we propose a role for adiponectin, visfatin and adipose clocks in the regulation of migratory behaviors.
Orlando Miguel Saucedo Castillo
Full Text Available In order to reduce the damages granivorous birds cause to sorghum (Sorghum bicolor L. Moench in the province of Villa Clara, Cuba, research based on the determination of the major endemic, migratory birds and their relationship with the distribution were made space of historical meteorological variables in the province in the seasonal behavior of birds in different climatic regions. Population to sorghum producers grouped in different forms surveys were conducted, which yielded a large database, such as the determination of the main grain-eating birds percentage damage incurred, varieties, grain color, growth stage and other indicators. Nine main species affecting sorghum grain-eating birds in our province were recorded; Passer domesticus, Lonchura malacca, Lonchura punctulata, Dives atroviolaceus, Passerina cyanea, Zonotrichia leucophrys, Columbina passerine, Zenaida macroura y Zenaida asiatica. The spatial distribution of meteorological variables and their relation to the seasonal behavior of birds in different climatic regions of the province was determined, based on record four preferential habitat areas. The results allowed us to provide companies and different forms of production in Villa Clara, the possibility of a varietal structure planting of sorghum on the basis of different preferential areas granivorous birds, together with the morphological and physiological characteristics of different genotypes introduced in agricultural production of the province and nationally.
MALDONADO PACHECO, KARIN
Debido a que el rango de distribución de las especies incluye diferentesambientes con características bióticas y abióticas generalmente contrastantes, laadecuación de los distintos genotipos de una misma especie a menudo difiereentre un hábitat y otro. De esta manera, la variabilidad en las característicasecológicas que experimentan las poblaciones podría promover diferencias interpoblacionales en la expresión y flexibilidad de los rasgos fisiológicos,morfológicos y conductuales, afectando fi...
Breuner, Creagh W; Sprague, Rachel S; Patterson, Stephen H; Woods, H Arthur
Severe storms can pose a grave challenge to the temperature and energy homeostasis of small endothermic vertebrates. Storms are accompanied by lower temperatures and wind, increasing metabolic expenditure, and can inhibit foraging, thereby limiting energy intake. To avoid these potential problems, most endotherms have mechanisms for offsetting the energetic risks posed by storms. One possibility is to use cues to predict oncoming storms and to alter physiology and behavior in ways that make survival more likely. Barometric pressure declines predictably before inclement weather, and several lines of evidence indicate that animals alter behavior based on changes in ambient pressure. Here we examined the effects of declining barometric pressure on physiology and behavior in the white-crowned sparrow, Zonotrichia leucophrys. Using field data from a long-term study, we first evaluated the relationship between barometric pressure, storms and stress physiology in free-living white-crowned sparrows. We then manipulated barometric pressure experimentally in the laboratory and determined how it affects activity, food intake, metabolic rates and stress physiology. The field data showed declining barometric pressure in the 12-24 h preceding snowstorms, but we found no relationship between barometric pressure and stress physiology. The laboratory study showed that declining barometric pressure stimulated food intake, but had no effect on metabolic rate or stress physiology. These data suggest that white-crowned sparrows can sense and respond to declining barometric pressure, and we propose that such an ability may be common in wild vertebrates, especially small ones for whom individual storms can be life-threatening events.
Full Text Available In the present study, we investigated types of pancreatic endocrine cells and its respective peptides in the Brazilian sparrow species using immunocytochemistry. The use of polyclonal specific antisera for somatostatin, glucagon, avian pancreatic polypeptide (APP, YY polypeptide (PYY and insulin, revealed a diversified distribution in the pancreas. All these types of immunoreactive cells were observed in the pancreas with different amounts. Insulin- Immunoreactive cells to (B cells were most numerous, preferably occupying the central place in the pancreatic islets. Somatostatin, PPA, PYY and glucagon immunoreactive cells occurred in a lower frequency in the periphery of pancreatic islets.
Fraga, Rosendo M.
Data on the brood parasitism of the Shiny Cowbird, Molothrus bonariensis on the Rufous-collared Sparrow, Zonotrlchia capensis, was collected during 10 breeding seasons (l970-1979: 70 nests), in a study site at Buenos Aires Province, Argentina. Though the cowbird parasitised 14 species of local passerines (40 %"of the total) most parasitic fledglings (46%), were reared by the sparrows. During the breeding season sparrows considerably outnumbered the cowbirds. Home ranges of banded female cowbi...
Elizabeth P Derryberry
Full Text Available Soundscapes pose both evolutionarily recent and long-standing sources of selection on acoustic communication. We currently know more about the impact of evolutionarily recent human-generated noise on communication than we do about how natural sounds such as pounding surf have shaped communication signals over evolutionary time. Based on signal detection theory, we hypothesized that acoustic phenotypes will vary with both anthropogenic and natural background noise levels and that similar mechanisms of cultural evolution and/or behavioral flexibility may underlie this variation. We studied song characteristics of white-crowned sparrows (Zonotrichia leucophrys nuttalli across a noise gradient that includes both anthropogenic and natural sources of noise in San Francisco and Marin counties, California, USA. Both anthropogenic and natural soundscapes contain high amplitude low frequency noise (traffic or surf, respectively, so we predicted that birds would produce songs with higher minimum frequencies in areas with higher amplitude background noise to avoid auditory masking. We also anticipated that song minimum frequencies would be higher than the projected lower frequency limit of hearing based on site-specific masking profiles. Background noise was a strong predictor of song minimum frequency, both within a local noise gradient of three urban sites with the same song dialect and cultural evolutionary history, and across the regional noise gradient, which encompasses 11 urban and rural sites, several dialects, and several anthropogenic and natural sources of noise. Among rural sites alone, background noise tended to predict song minimum frequency, indicating that urban sites were not solely responsible for driving the regional pattern. These findings support the hypothesis that songs vary with local and regional soundscapes regardless of the source of noise. Song minimum frequency from five core study sites was also higher than the lower frequency
Dingle, Caroline; Poelstra, Jelmer W.; Halfwerk, Wouter; Brinkhuizen, Dusan M.; Slabbekoorn, Hans
Song divergence between closely related taxa may play a critical role in the evolutionary processes of speciation and hybridization. We explored song variation between two Ecuadorian subspecies of the gray-breasted wood-wren (Henicorhina leucophrys) and tested the impact of song divergence on respon
Lynn, Suellen; Madden, Melanie C.; Kus, Barbara E.
Executive SummaryWe operated a bird banding station on the Point Loma peninsula in western San Diego County, California, during spring and summer from 2011 to 2015. The station was established in 2010 as part of a long-term monitoring program for neotropical migratory birds during spring migration and for breeding birds as part of the Monitoring Avian Productivity and Survivorship (MAPS) program.During spring migration (April and May), 2011–15, we captured 1,760 individual birds of 54 species, 91 percent (1,595) of which were newly banded, fewer than 1 percent (3) of which were recaptures that were banded in previous years, and 9 percent (143 hummingbirds, 2 hawks, and 17 other birds) of which we released unbanded. We observed an additional 22 species that were not captured. Thirty-four individuals were captured more than once. Bird capture rate averaged 0.49 ± 0.07 captures per net-hour (range 0.41–0.56). Species richness per day averaged 6.87 ± 0.33. Cardellina pusilla (Wilson’s warbler) was the most abundant spring migrant captured, followed by Empidonax difficilis (Pacific-slope flycatcher), Vireo gilvus (warbling vireo), Zonotrichia leucophrys (white-crowned sparrow), and Selasphorus rufus (rufous hummingbird). Captures of white-crowned sparrow decreased, and captures of Pacific-slope flycatcher increased, over the 5 years of our study. Fifty-six percent of known-sex individuals were male and 44 percent were female. The peak number of new species arriving per day ranged from April 1 (2013-six species) to April 16 (2012-five species). A significant correlation was determined between the number of migrants captured each day per net-hour and the density of echoes on the Next-Generation Radar (NEXRAD) images across all 5 years, and in each year except 2014. NEXRAD radar imagery appears to be a useful tool for detecting pulses in migration.Our results indicate that Point Loma provides stopover habitat during migration for 76 migratory species, including 20
Bochkov, Andre V; Skoracki, Maciej; Hendricks, Sarah A; Spicer, Greg S
Four new syringophilid species of Syringophiloidus Kethley, 1970 are described from North American passerines: S. zonotrichia n. sp. from Zonotrichia albicolis (Gmelin) (Emberizidae) on Texas; S. jackowiaki n. sp. from Poecile carolinensis (Auduborn) (Paridae) in Texas; and S. xanthocephalus n. sp. from Xanthocephalus xanthocephalus (Bonaparte) (Icteridae) and S. agelaius n. sp. from Agelaius phoeniceus Linnaeus (Icteridae), both from Arizona. Spizella breweri (Cassin) (Emberizidae) from California is a new host for Syringophiloidus sialius Skoracki, Flannery & Spicer, 2009; and Melospiza lincolnii (Auduborn) (Emberizidae) from Texas and Vermivora ruficapilla (Wilson) (Parulidae) from California are new hosts for S. seiuri (Ckark, 1964). S. daberti Bochkov, Fain & Skoracki, 2004 from Passerina ciris Linnaeus (Cardinalidae) is recorded in the USA for the first time. A table with the host associations and distribution of all of the North American species of Syringophiloidus is given.
Kevin C. Hannah; Fiona K.A. Schmiegelow; Kathryn E. H. Aitken
The use of density to measure a species' responses to habitat change remains prevalent despite warnings that relying on such parameters can be misleading. We evaluated whether density was a useful surrogate of habitat quality for the White-throated Sparrow (Zonotrichia albicollis), an apparent habitat generalist, in a recently logged landscape near Calling Lake, Alberta, Canada. We detected significant differences in the territory density of birds among three distinct habitat types: inte...
Miller, Alden H.
Para el estudio de los ciclos reproductivos de las aves cerca al ecuador se seleccionó el Gorrión (Zonotrichia capensis) teniendo en cuenta que se han realizado estudios intensivos en especies próximas que habitan el hemisferio norte. Se escogió como estación de trabajo, el sitio denominado Mares localizado en la cima de la Cordillera Occidental sobre la carretera que conduce de Cali a Buenaventura. Mediante trabajos de anillado, instalación de trampas para captura de las aves, realización d...
Dolibaina, Diego Rodrigo; Dias, Fernando Maia Silva; Siewert, Ricardo Russo; Mielke, Olaf Hermann Hendrik; Casagrande, Mirna Martins
The species of Mesene Doubleday, 1847 collected at the Parque Nacional da Serra do Divisor, Acre, Brazil (PNSD) are listed and supplemented by taxonomic and behavioral notes. In total, 30 specimens were collected, representing seven species including one new: M. monostigma monostigma (Erichson, ), M. nepticula stigmosa Stichel, 1910, M. eupteryx Bates, 1868 stat. rest., M. paraena Bates, 1868, M. epaphus pyrrha Bates, 1868, M. leucophrys Bates, 1868, and M. gracielae sp. nov. The following notes on the taxonomy of Mesene are proposed: M. eupteryx Bates, 1868 stat. rest. is recognized as a valid species, M. epaphus sertata Stichel, 1910 syn. nov. is a new synonym of M. epaphus pyrrha Bates, 1868, and M. lecointrei P. Jauffret & J. Jauffret, 2008 syn. nov. is a new synonym of M. philonis Hewitson, 1874. Mesene margaretta (White, 1843), M. philonis and M. nola are recognized as closely related. Species encountered at the PNSD are illustrated, including the genitalia of males and females, when available.
Shizuka, Daizaburo; Chaine, Alexis S; Anderson, Jennifer; Johnson, Oscar; Laursen, Inger Marie; Lyon, Bruce E
Migratory birds often form flocks on their wintering grounds, but important details of social structure such as the patterns of association between individuals are virtually unknown. We analysed networks of co-membership in short-term flocks for wintering golden-crowned sparrows (Zonotrichia atricapilla) across three years and discovered social complexity unsuspected for migratory songbirds. The population was consistently clustered into distinct social communities within a relatively small area (~ 7 ha). Birds returned to the same community across years, with mortality and recruitment leading to some degree of turnover in membership. These spatiotemporal patterns were explained by the combination of space use and social preference - birds that flocked together in one year flocked together again in the subsequent year more often than were expected based on degrees of home range overlap. Our results suggest that a surprising level of social fidelity across years leads to repeatable patterns of social network structure in migratory populations.
Full Text Available ( AC235776 ) Zonotrichia albicollis clone CH264-226A16, WORKIN... 52 0.021 1 ( AC169893 ) Macaca mulatta clone CH250-286A2, WORK...ING DRAFT S... 46 0.022 2 ( AC008452 ) Homo sapiens chromosome 5 clone CTC-345F2, WORKIN... musculus chromosome 5 clone RP23-286B6 map 5,... 50 0.084 1 ( AC129749 ) Rattus norvegicus clone CH230-50O23, WORK... AC099075 ) Rattus norvegicus clone CH230-41C6, WORKING DRAFT... 50 0.084 1 ( AC0...98172 ) Rattus norvegicus clone CH230-160H21, WORKING DRA... 50 0.084 1 ( AC096311 ) Rattus norvegicus clone CH230-126I16, WORK
de Souza Lopes, O; Coimbra, T L; de Abreu Sacchetta, L; Calisher, C H
In April, 1975, an epidemic of human encephalitis was detected in several counties in the State of São Paulo, Brazil; the epidemic continued into 1976. A virus was isolated from central nervous system (CNS) tissues of a 39-year-old male who died on December 8, 1975; the virus was found to be a new flavivirus for which the name Rocio virus is proposed. Nine further isolations of Rocio virus were obtained from CNS tissues of 17 patients who died with clinical symptoms of encephalitis. Isolations of virus and serologic evidence of Rocio virus infection in a significant proportion of the encephalitis patients suggested that Rocio virus was the etiologic agent of the epidemic. Rocio virus was isolated only from patients who died within 5 days of onset of illness. The virus was isolated from two sentinel mice exposed in the epidemic zone and from a rufous collared sparrow (Zonotrichia capensis) collected in the area.
Price, Edwin R; Staples, James F; Milligan, C Louise; Guglielmo, Christopher G
Birds primarily fuel migratory flights with fat, and the composition of that fat has the potential to affect overall lipid oxidation rates. We measured the whole muscle lipid oxidation rates in extensor digitorum communis muscles from white-throated sparrows (Zonotrichia albicollis Gmelin) incubated for 20 min at 20°C with radiolabeled stearate (18:0), oleate (18:1ω9), or linoleate (18:2ω6). Lipid oxidation rates were ~40% higher with linoleate than oleate (oleate: 36 ± 8.54 μmol CO(2) g(-1) h(-1)), and ~75% lower with stearate compared with oleate, indicating that maximal lipid oxidation rates can indeed be affected by the type of fatty acid supplied to the muscle. Additionally, we investigated the activity of the mitochondrial fatty acid transport-associated enzyme carnitine palmitoyl transferase (CPT) in pectoralis muscles of 5 bird species (Zonotrichia albicollis, Philomachus pugnax, Sturnus vulgaris, Taeniopygia guttata, Passer domesticus). Activity was measured in homogenized samples using various fatty acyl-CoA substrates (16:0, 16:1, 18:0, 18:1ω9, 18:2ω6, 18:3ω3, 18:3ω6, 20:0, 20:4ω6, 22:6ω3) in a spectrophotometric assay. CPT activity increased with the degree of unsaturation and decreased with chain length. CPT activity did not differ between ω3 and ω6 isomers of 18:3, nor was the pattern of CPT substrate preference different between captive white-throated sparrows in a migratory (i.e., displaying Zugunruhe) or non-migratory state. These findings can explain previously observed differences in peak performance induced by dietary fat composition and suggest that lipid supply is limiting to maximal exercise performance in birds.
Oswaldo Marçal Júnior
Full Text Available This work aimed to determine the richness of the avifauna of the Municipal Park of Sabiá, urban perimeter of the municipality of Uberlândia (Brazil, and also to evaluate possible differences in composition among the several landscapes in the study area. The work was accomplished from July 2000 to November 2002, including at least one month of observation in the period of the morning (7:00-11:00 and totalling 33 visits (334 hours. The registrations were made along a transect that crossed different landscapes. A total of 149 species distributed in 16 orders, 38 families and 131 genders were recorded. Five species of endemic birds of the Cerrado were present in the survey: Herpsilochmus longirostris, Hylocryptus rectirostris, Antilophia galeata, Cyanocorax cristatellus and Basileuterus leucophrys. Most of the birds (80% were classified as residents or probable residents in the Park. The main alimentary guilds were insectivorous (n = 52; 35%, omnivorous (n = 46; 31% and frugivorous (n = 13; 9%. All areas were considered similar and had a Sorensen index above 0.80, probably associated with the proximity and connectivity of the investigated areas. The results indicate that the Park of Sabiá can be considered an important location for the maintenance of the regional avifauna.
Eisermann, Knut; Schulz, Ulrich
The Northern Central American Highlands have been recognized as endemic bird area, but little is known about bird communities in Guatemalan cloud forests. From 1997 to 2001 a total of 142 bird species were recorded between 2000 and 2400 masl in cloud forest and agricultural clearings on Montaña Caquipec (Alta Verapaz, Guatemala). The bird community is described based on line transect counts within the forest. Pooling census data from undisturbed and disturbed forest, the Gray-breasted Wood-Wren (Henicorhina leucophrys) was found to be the most abundant species, followed in descending order by the Common Bush-Tanager (Chlorospingus ophthalmicus), the Paltry Tyrannulet (Zimmerius vilissimus), the Yellowish Flycatcher (Empidonax flavescens), the Ruddy-capped Nightingale-Thrush (Catharus frantzi), and the Amethyst-throated Hummingbird (Lampornis amethystinus). Bird communities in undisturbed and disturbed forest were found to be similar (Serensen similarity index 0.85), indicating low human impact. Of all recorded species, approximately 27% were Nearctic-Neotropical migratory birds. The most abundant one was the Wilson's Warbler (Wilsonia pusilla). The Montaña Caquipec is an important area for bird conservation, which is indicated by the presence of four species listed in the IUCN Red List (Highland Guan Penelopina nigra, Resplendent Quetzal Pharomachrus mocinno, Pink-headed Warbler Ergaticus versicolor, Golden-cheeked Warbler Dendroica chrysoparia), and 42 Mesoamerican endemics, of which 14 species are endemic to the Central American Highlands. The results presented here will be useful as baseline data for a long-term monitoring.
Ginnett, Dorothy A; Theis, Jerold H; Kaneko, J Jerry
A study of the physiologic and ecologic factors involved in a spontaneous seasonal gallstone cycle of deer mice (Peromyscus maniculatus gambelii) was conducted at the Tulelake National Wildlife Refuge (California, USA) from March 1991 to June 1992. The specific hypothesis examined was whether or not seasonal increases in dietary fiber intake provides the necessary conditions for a solubility defect, or supersaturation mechanism, resulting in precipitation of cholesterol gallstones. Results indicated that in addition to the seasonal gallstone prevalence cycle, these deer mice exhibit significant seasonal cycling in serum cholesterol, serum bile acids, fecal bile acids, and diet composition. These physiologic and dietary cycles were phase-advanced 3 mo over the gallstone prevalence cycle, indicating an approximate 3 mo time period for gallstone formation under field conditions. Further, seasonal dietary fiber (plant material and seeds) was positively correlated with both serum cholesterol and the fecal bile acids. This suggests that in wild deer mice, variations in dietary fiber may significantly affect the resorption of bile acids, thereby providing a potential physiologic and nutritional mechanism for spontaneous cholesterol gallstone formation.
Full Text Available The Northern Central American Highlands have been recognized as endemic bird area, but little is known about bird communities in Guatemalan cloud forests. From 1997 to 2001 a total of 142 bird species were recorded between 2 000 and 2 400 masl in cloud forest and agricultural clearings on Montaña Caquipec (Alta Verapaz, Guatemala. The bird community is described based on line transect counts within the forest. Pooling census data from undisturbed and disturbed forest, the Gray-breasted Wood-Wren (Henicorhina leucophrys was found to be the most abundant species, followed in descending order by the Common Bush-Tanager (Chlorospingus ophthalmicus, the Paltry Tyrannulet (Zimmerius vilissimus, the Yellowish Flycatcher (Empidonax flavescens, the Ruddy-capped Nightingale-Thrush (Catharus frantzii, and the Amethyst-throated Hummingbird (Lampornis amethystinus. Bird communities in undisturbed and disturbed forest were found to be similar (Sørensen similarity index 0.85, indicating low human impact. Of all recorded species, ~27% were Nearctic-Neotropical migratory birds. The most abundant one was the Wilson’s Warbler (Wilsonia pusilla. The Montaña Caquipec is an important area for bird conservation, which is indicated by the presence of four species listed in the IUCN Red List (Highland Guan Penelopina nigra, Resplendent Quetzal Pharomachrus mocinno, Pink-headed Warbler Ergaticus versicolor, Golden-cheeked Warbler Dendroica chrysoparia, and 42 Mesoamerican endemics, of which 14 species are endemic to the Central American Highlands. The results presented here will be useful as baseline data for a long-term monitoring. Rev. Biol. Trop. 53(3-4: 577-594. Epub 2005 Oct 3.Las alturas del norte de Centroamérica han sido reconocidas como región de aves endémicas, pero se conoce poco sobre las comunidades de aves en bosques nubosos de Guatemala. De 1997 a 2001 se han detectado 142 especies de aves entre 2 000 y 2 400 msnm en el bosque nuboso y áreas agr
Full Text Available Taxonomic study of Leschenaultia Robineau-Desvoidy (Diptera, Tachinidae. The genus Leschenaultia Robineau-Desvoidy, 1830 is redescribed. Two genera are considered as its junior synonyms: Echinomasicera Townsend, 1915 syn. nov. and Parachaetopsis Blanchard, 1959 syn. nov. Thirty two especies are treated, as follows: 18 described as new, Leschenaultia aldrichi, sp. nov. (Brazil, Santa Catarina, L. arnaudi sp. nov. (Haiti, La Salle, L. bergenstammi sp. nov. (Peru, San Martin, L. bessi sp. nov. (Brazil, Santa Catarina, L. bigoti sp. nov. (Peru, Huanuco, L. blanchardi sp. nov. (Equador, Cuenca, L. braueri sp. nov. (Brazil, Mato Grosso, L. brooksi sp. nov. (Brazil, Rio de Janeiro, L. coquilletti sp. nov. (Brazil, Santa Catarina; L. cortesi sp. nov. (Venezuela, Maracay, L. currani sp. nov. (Brazil, São Paulo, L. loewi sp. nov. (Mexico, Vera Cruz, L. macquarti sp. nov. (U. S. A., Arizona, L. reinhardi sp. nov. (Canada, Quebec, L. sabroskyi sp. nov. from (U. S. A., California, L. schineri sp. nov. (U. S. A., California, L. thompsoni sp. nov. (Mexico, Mexico City, L. townsendi sp. nov. (Mexico, Puebla, and 14 known species, for these, diagnoses are given: L. adusta (Loew, 1872; L. americana (Brauer & Bergenstamm, 1893; L. bicolor (Macquart, 1846 = L. fusca (Townsend, 1916 syn. nov.; = Parachaetopsis proseni Blanchard, 1959 syn. nov.; L. ciliata (Macquart, 1848; L. exul (Townsend, 1892; L. fulvipes (Bigot, 1887; L. grossa Brooks, 1947; L. halisidotae Brooks, 1947; L. hospita Reinhard, 1952; L. hystrix (Townsend, 1915 comb. nov., L. jurinioides (Townsend, 1895; L. leucophrys (Wiedemann, 1830 = Leschenaultia latifrons (Walker, 1852 syn. nov. = Parachaeta nigricalyptrata (Macquart, 1855 syn. nov.; L. montagna (Townsend, 1912; L. nuda Thompson, 1963. One species was not examined, Leschenaultia nigrisquamis (Townsend, 1892, and two were not recognized, L. trichopsis (Bigot, 1887 and L. hirta Robineau-Desvoidy, 1830. Keys for Nearctic and Neotropical species
Darrell B. Roundy
Full Text Available Expansion of Pinus L. (pinyon and Juniperus L. (juniper (P-J trees into sagebrush (Artemisia L. steppe communities can lead to negative effects on hydrology, loss of wildlife habitat, and a decrease in desirable understory vegetation. Tree reduction treatments are often implemented to mitigate these negative effects. In order to prioritize and effectively plan these treatments, rapid, accurate, and inexpensive methods are needed to estimate tree canopy cover at the landscape scale. We used object based image analysis (OBIA software (Feature AnalystTM for ArcMap 10.1®, ENVI Feature Extraction®, and Trimble eCognition Developer 8.2® to extract tree canopy cover using NAIP (National Agricultural Imagery Program imagery. We then compared our extractions with ground measured tree canopy cover (crown diameter and line point intercept on 309 plots across 44 sites in Utah. Extraction methods did not consistently over- or under-estimate ground measured P-J canopy cover except where tree cover was >45%. Estimates of tree canopy cover using OBIA techniques were strongly correlated with estimates using the crown diameter method (r = 0.93 for ENVI, 0.91 for Feature AnalystTM, and 0.92 for eCognition. Tree cover estimates using OBIA techniques had lower correlations with tree cover measurements using the line-point intercept method (r = 0.85 for ENVI, 0.83 for Feature AnalystTM, and 0.83 for eCognition. All software packages accurately and inexpensively extracted P-J canopy cover from NAIP imagery when the imagery was not blurred, and when P-J cover was not mixed with Amelanchier alnifolia (Utah serviceberry and Quercus gambelii (Gambel’s oak, which had similar spectral values as P-J.
Helmig, Detlev; Daly, Ryan Woodfin; Milford, Jana; Guenther, Alex
Biogenic volatile organic compound (BVOC) emissions from six coniferous tree species, i.e. Pinus ponderosa (Ponderosa Pine), Picea pungens (Blue Spruce), Pseudotsuga menziesii (Rocky Mountain Douglas Fir) and Pinus longaeva (Bristlecone Pine), as well as from two deciduous species, Quercus gambelii (Gamble Oak) and Betula occidentalis (Western River Birch) were studied over a full annual growing cycle. Monoterpene (MT) and sesquiterpene (SQT) emissions rates were quantified in a total of 1236 individual branch enclosure samples. MT dominated coniferous emissions, producing greater than 95% of BVOC emissions. MT and SQT demonstrated short-term emission dependence with temperature. Two oxygenated MT, 1,8-cineol and piperitone, were both light and temperature dependent. Basal emission rates (BER, normalized to 1000μmolm(-2)s(-1) and 30°C) were generally higher in spring and summer than in winter; MT seasonal BER from the coniferous trees maximized between 1.5 and 6.0μgg(-1)h(-1), while seasonal lows were near 0.1μgg(-1)h(-1). The fractional contribution of individual MT to total emissions was found to fluctuate with season. SQT BER measured from the coniferous trees ranged from temperature dependence in emissions modeling, was not found to exhibit discernible growth season trends. A seasonal correction factor proposed by others in previous work to account for a sinusoidal shaped emission pattern was applied to the data. Varying levels of agreement were found between the data and model results for the different plant species seasonal data sets using this correction. Consequently, the analyses on this extensive data set suggest that it is not feasible to apply a universal seasonal correction factor across different vegetation species. A modeling exercise comparing two case scenarios, (1) without and (2) with consideration of the seasonal changes in emission factors illustrated large deviations when emission factors are applied for other seasons than those in which
Bush, S. E.; Hultine, K. R.; Ehleringer, J. R.
Thermal dissipation probes for measuring sap flow (Granier-type) at the whole tree and stand level are routinely used in forest ecology and site water balance studies. While the original empirical relationship used to calculate sap flow was reported as independent of wood anatomy (ring-porous, diffuse-porous, tracheid), it has been suggested that potentially large errors in sap flow calculations may occur when using the original calibration for ring-porous species, due to large radial trends in sap velocity and/or shallow sapwood depth. Despite these concerns, sap flux measurements have rarely been calibrated in ring-porous taxa. We used a simple technique to calibrate thermal dissipation sap flux measurements on ring-porous trees in the lab. Calibration measurements were conducted on five ring-porous species in the Salt Lake City, USA metropolitan area including Quercus gambelii (Gambel oak), Gleditsia triacanthos (Honey locust), Elaeagnus angustifolia (Russian olive), Sophora japonica (Japanese pagoda), and Celtis occidentalis (Common hackberry). Six stems per species of approximately 1 m in length were instrumented with heat dissipation probes to measure sap flux concurrently with gravimetric measurements of water flow through each stem. Safranin dye was pulled through the stems following flow rate measurements to determine sapwood area. As expected, nearly all the conducting sapwood area was limited to regions within the current year growth rings. Consequently, we found that the original Granier equation underestimated sap flux density for all species considered. Our results indicate that the use of thermal dissipation probes for measuring sap flow in ring-porous species should be independently calibrated, particularly when species- specific calibration data are not available. Ring-porous taxa are widely distributed and represent an important component of the regional water budgets of many temperate regions. Our results are important for evaluating plant water
Ecological niche models (ENMs) have increasingly been used to estimate the potential effects of climate change on species’ distributions worldwide. Recently, predictions of species abundance have also been obtained with such models, though knowledge about the climatic variables affecting species abundance is often lacking. To address this, we used a well-studied guild (temperate North American quail) and the Maxent modeling algorithm to compare model performance of three variable selection approaches: correlation/variable contribution (CVC), biological (i.e., variables known to affect species abundance), and random. We then applied the best approach to forecast potential distributions, under future climatic conditions, and analyze future potential distributions in light of available abundance data and presence-only occurrence data. To estimate species’ distributional shifts we generated ensemble forecasts using four global circulation models, four representative concentration pathways, and two time periods (2050 and 2070). Furthermore, we present distributional shifts where 75%, 90%, and 100% of our ensemble models agreed. The CVC variable selection approach outperformed our biological approach for four of the six species. Model projections indicated species-specific effects of climate change on future distributions of temperate North American quail. The Gambel’s quail (Callipepla gambelii) was the only species predicted to gain area in climatic suitability across all three scenarios of ensemble model agreement. Conversely, the scaled quail (Callipepla squamata) was the only species predicted to lose area in climatic suitability across all three scenarios of ensemble model agreement. Our models projected future loss of areas for the northern bobwhite (Colinus virginianus) and scaled quail in portions of their distributions which are currently areas of high abundance. Climatic variables that influence local abundance may not always scale up to influence
Full Text Available Migrating birds may respond to a variety of environmental cues in order to time migration. During the migration season nocturnally migrating songbirds may migrate or stop-over at their current location, and when migrating they may vary the rate or distance of migration on any given night. It has long been known that a variety of weather-related factors including wind speed and direction, and temperature, are correlated with migration in free-living birds, however these variables are often correlated with each other. In this study we experimentally manipulated temperature to determine if it would directly modulate nocturnal migratory restlessness in songbirds. We experimentally manipulated temperature between 4, 14, and 24°C and monitored nocturnal migratory restlessness during autumn in white-throated sparrows (Zonotrichia albicollis. White-throated sparrows are relatively shortdistance migrants with a prolonged autumnal migration, and we thus predicted they might be sensitive to weatherrelated cues when deciding whether to migrate or stopover. At warm temperatures (24°C none of the birds exhibited migratory restlessness. The probability of exhibiting migratory restlessness, and the intensity of this restlessness (number of infra-red beam breaks increased at cooler (14°C, 4°C temperatures. These data support the hypothesis that one of the many factors that birds use when making behavioural decisions during migration is temperature, and that birds can respond to temperature directly independently of other weather-related cues.
Skoracki, Maciej; Spicer, Greg S; Oconnor, Barry M
Quill mites belonging to the subfamily Syringophilinae Lavoipierre, 1953 associated with the Nearctic passeriform birds are revised. All of the 49 known species, which are grouped in seven genera, are recorded. Among them, four new species are described: Syringophiloidus audubioni sp. nov. from Spizella breweri (Cassini) (Emberizidae), Syringophilopsis catesbyi sp. nov. from Vireo olivaceus (Linnaeus) (Vireonidae), S. wilsoni sp. nov. from Pheucticus melanocephalus (Swainson) (Cardinalidae), and S. bartrami sp. nov. from Spizella passerina (Bechstein) (Emberizidae). The species Syringophilopsis hylocichlae Clark, 1964 syn. nov. is synonymized with Syringophilopsis turdus (Fritsch, 1958), and Syringophiloidus zonotrichia syn. nov. is synonymized with Betasyringophiloidus seiuri (Clark, 1964) comb. nov. Six species are recorded from the Nearctic region for the first time: Syringophiloidus delichonum Bochkov, 2001, S. glandarii (Fritsch, 1958), S. weiszii Skoracki et al., 2001, S. bombycillae Skoracki, 2002, Syringophilopsis mimidus Sikora et al., 2011, and Torotrogla merulae Skoracki et al., 2000. Data on Nearctic syringophiline species, their hosts and distribution are summarized and the keys to all species are constructed.
Carson, Rebecca J; Spicer, Greg S
Previous molecular phylogenetic studies have examined the taxonomic relationships among a number of typical emberizid sparrow genera. To help clarify these relationships, we sequenced a 1673 base pair fragment for the complete sequence of three mitochondrial genes: adenosine triphosphatase (Atp8 and Atp6) and cytochrome oxidase subunit III (COIII) for 38 sparrow species, along with Passerina amoena (Cardinalidae) and Piranga ludoviciana (Thraupidae) which were selected as the outgroups. Our analysis confirms the monophyly of traditional genera such as Junco, Melospiza, and Zonotrichia. Although Calcarius and Plectrophenax are often thought to be putative emberizids, all our analyses placed these genera basal to all other sparrows examined. As observed with Calcarius, Spizella did not form a monophyletic group, with S. arborea being the sister-taxon to Passerella iliaca. Our analyses also suggest that Aimophila ruficeps is probably more closely related to the "brown towhees" (Pipilo aberti, P. crissalis, and P. fuscus) than its putative congeners. The genus Ammodramus was also not monophyletic, since it appears that Passerculus sandwichensis is more closely related to A. henslowii and A. leconteii then either one is related to its congener A. savannarum. Finally, our analyses exhibited other unsuspected associations, such as the sister-taxon relationships between Amphispiza bilineata and the Chondestes grammacus/Calamospiza melanocorys clade, and Amphispiza belli and Pooecetes gramineus.
Blank, P.J.; Parks, J.R.; Dively, G.P.
Herbaceous buffers are strips of herbaceous vegetation planted between working agricultural land and streams or wetlands. Mowing is a common maintenance practice to control woody plants and noxious weeds in herbaceous buffers. Buffers enrolled in Maryland's Conservation Reserve Enhancement Program (CREP) cannot be mowed during the primary bird nesting season between 15 April and 15 August. Most mowing of buffers in Maryland occurs in late summer or fall, leaving the vegetation short until the following spring. We studied the response of wintering birds to fall mowing of buffers. We mowed one section to 10-15 cm in 13 buffers and kept another section unmowed. Ninety-two percent of birds detected in buffers were grassland or scrub-shrub species, and 98% of all birds detected were in unmowed buffers. Total bird abundance, species richness, and total avian conservation value were significantly greater in unmowed buffers, and Savannah Sparrows (Passerculus sandwichensis), Song Sparrows (Melospiza melodia), and White-throated Sparrows (Zonotrichia albicollis) were significantly more abundant in unmowed buffers. Wintering bird use of mowed buffers was less than in unmowed buffers. Leaving herbaceous buffers unmowed through winter will likely provide better habitat for wintering birds. ?? 2011 by the Wilson Ornithological Society.
Jeisson Alexander Mayorga
Full Text Available Se determinó la diversidad de aves de la vereda San Gil, municipio de Gutiérrez, Cundinamarca, durante los meses de octubre de 2012 a marzo de 2013, mediante el método de conteo por puntos. El área de estudio se dividió en cuatro transectos, identificándose cinco hábitats: páramo, subpáramo, bosque andino, cultivos y zonas intervenidas. Para la diversidad alfa se emplearon los índices de Fisher, Shannon-Wiener y Simpson; para abundancia relativa se utilizó la clasificación recomendada por Birdlife International; la diversidad beta estableció la similitud entre zonas mediante el índice de Jaccard. Se encontraron 1190 individuos distribuidos en 82 especies, 32 familias y 14 órdenes. Las familias con mayor número de especies fueron Trochilidae (12 sp., Tyrannidae (10 sp., Thraupidae (10 sp. y Emberizidae (5 sp.. La especie más abundante es Zonotrichia capensis. Las especies amenazadas son Pyrrhura Calliptera, Oxyura jamaicensis, Andigena nigrirostris y Spizaetus isidori.
Brent M Horton
Full Text Available In species with discrete morphs exhibiting alternative behavioral strategies, individuals may vary their aggressive behavior in competitive encounters according to the phenotype of their opponent. Such aggression bias has been documented in multiple polymorphic species evolving under negative frequency-dependent selection, but it has not been well-studied under other selection regimes. We investigated this phenomenon in white-throated sparrows (Zonotrichia albicollis, a passerine with plumage polychromatism maintained by disassortative mating. The two distinct color morphs differ with respect to reproductive strategy in that white-striped birds invest more in territorial aggression than tan-striped birds. Whether territorial aggression in this species is biased according to the morph of an intruder is less understood. We found that during peak territorial and mating activity, both color morphs and sexes can exhibit aggression bias, but whether they do so depends on the strategy (morph of the intruder. During simulated territorial intrusions, resident white-striped males and tan-striped females, which represent the opposite ends of a continuum from high to low territorial aggression, altered their territorial responses according to intruder morph. Tan-striped males and white-striped females, which represent the middle of the continuum, did not show a bias. We propose that because of the disassortative mating system and morph differences in reproductive strategy, the fitness risks of intrusions vary according to the morphs of the resident and the intruder, and that aggression bias is an attuned response to varying threats to fitness.
Seavy, Nathaniel E; Humple, Diana L; Cormier, Renée L; Gardali, Thomas
The migratory biology and connectivity of passerines remains poorly known, even for those that move primarily within the temperate zone. We used light-level geolocators to describe the migratory geography of a North American temperate migrant passerine. From February to March of 2010, we attached geolocator tags to 33 Golden-crowned Sparrows (Zonotrichia atricapilla) wintering on the central coast of California, USA, and recovered four tags the following winter (October to December 2010). We used a bayesian state-space model to estimate the most likely breeding locations. All four birds spent the breeding season on the coast of the Gulf of Alaska. These locations spanned approximately 1200 kilometers, and none of the individuals bred in the same location. Speed of migration was nearly twice as fast during spring than fall. The return rate of birds tagged the previous season (33%) was similar to that of control birds (39%), but comparing return rates was complicated because 7 of 11 returning birds had lost their tags. For birds that we recaptured before spring migration, we found no significant difference in mass change between tagged and control birds. Our results provide insight into the previously-unknown breeding provenance of a wintering population of Golden-crowned Sparrows and provide more evidence of the contributions that light-level geolocation can make to our understanding of the migratory geography of small passerines.
Alan, Rebecca R; McWilliams, Scott R
Oxidative stress is an unavoidable consequence of metabolism and increases during intensive exercise. This is especially problematic for migratory birds that metabolize fat to fuel long-distance flight. Birds can mitigate damage by increasing endogenous antioxidants (e.g. uric acid) or by consuming dietary antioxidants (e.g. tocopherol). During flight, birds may increase protein catabolism of lean tissue which may increase circulating uric acid and many birds also consume an antioxidant-rich frugivorous diet during autumn migration. We evaluated three related hypotheses in a migratory passerine: (1) protein consumption is positively related to circulating antioxidants, (2) a dietary oxidative stressor [i.e. polyunsaturated fatty acid (PUFA)] influences antioxidant capacity and oxidative damage, and (3) oxidative stress influences dietary antioxidant preferences. White-throated Sparrows (Zonotrichia albicollis) consuming a high protein diet increased circulating uric acid; however, uric acid, antioxidant capacity, and oxidative stress did not differ between birds consuming a high PUFA versus a low PUFA diet, despite increased oxidative damage in high PUFA birds. Birds did not prefer antioxidant-rich diets even when fed high PUFA, low protein. We conclude that White-throated Sparrows successfully mitigated oxidative damage associated with a high PUFA diet and mounted an endogenous antioxidant response independent of uric acid, other circulating antioxidants, and dietary antioxidants.
Heller, Erin L; Wright, Chelsea L; Nadolny, Robyn M; Hynes, Wayne L; Gaff, Holly D; Walters, Eric L
Ixodes affinis Neumann (Acari: Ixodidae) is a hard-bodied tick species distributed throughout much of the southeastern United States. Although I. affinis does not parasitize humans, it is a competent vector of Borrelia burgdorferi sensu stricto, the causative-agent of Lyme disease, and thus contributes to the enzootic maintenance of this pathogen. This study presents evidence of I. affinis parasitizing five new host passerine species. During 2012-2014, 1,888 birds were captured and examined for ticks, and 18 immature I. affinis were collected from 12 birds-six Carolina Wrens (Thyrothorus ludovicianus); two Brown Thrashers (Toxostoma rufum); and one American Robin (Turdus migratorius), Eastern Towhee (Pipilo erythrophthalmus), Northern Cardinal (Cardinalis cardinalis), and White-throated Sparrow (Zonotrichia albicollis). Of 15 larvae and 3 nymphs collected, one nymph tested positive for B. burgdorferi DNA. I. affinis was found co-feeding on birds with immature Amblyomma americanum (L.), Ixodes brunneus Koch, Ixodes dentatus Marx, Ixodes scapularis Say, and Haemaphysalis leporispalustris Packard. The results of this research provide a better understanding of I. affinis hosts and identify avian taxa that may play a role in the maintenance and dispersal of this tick species.
Riede, Tobias; Suthers, Roderick A
Bird song is a complex behavior that requires the coordination of several motor systems. Sound is produced in the syrinx and then modified by the upper vocal tract. Movements of the hyoid skeleton have been shown in the northern cardinal (Cardinalis cardinalis) to be extensively involved in forming an oropharyngeal-esophageal cavity (OEC), which contributes a major resonance to the vocal tract transfer function. Here we report that a similar relationship exists between the volume of the OEC and the fundamental frequency in the white-throated sparrow (Zonotrichia albicollis) whose song, unlike that of the cardinal, consists of a series of almost constant frequency notes. Cineradiography of singing sparrows shows that the oropharyngeal cavity and cranial end of the esophagus expand abruptly at the start of each note and maintain a relatively constant volume until the end of the note. Computation of the vocal tract transfer function suggests a major resonance of the OEC follows the fundamental frequency, making sound transmission more efficient. The presence of similar prominent song-related vocal tract motor patterns in two Oscine families suggests that the active control of the vocal tract resonance by varying the volume of the OEC may be widespread in songbirds.
Muheim, Rachel; Phillips, John B; Deutschlander, Mark E
The interaction and hierarchy of celestial and magnetic compass cues used by migratory songbirds for orientation has long been the topic of an intense debate. We have previously shown that migratory Savannah sparrows, Passerculus sandwichensis, use polarized light cues near the horizon at sunrise and sunset to recalibrate their magnetic compass. Birds exposed to a +/-90 deg. shifted artificial polarization pattern at sunrise or sunset recalibrated their magnetic compass, but only when given full access to celestial cues, including polarized light cues near the horizon. In the current study, we carried out cue conflict experiments with white-throated sparrows, Zonotrichia albicollis, during both spring and autumn migration in a transition zone between the species' breeding and wintering areas on the south shore of Lake Ontario. We show that white-throated sparrows also recalibrate their magnetic compass by polarized light cues at sunrise and sunset. Sunrise exposure to an artificial polarization pattern shifted relative to the natural magnetic field or exposure to a shift of the magnetic field relative to the natural sky both led to recalibration of the magnetic compass, demonstrating that artificial polarizing filters do not create an anomalous, unnatural orientation response. Our results further indicate that there is no evidence for a difference in compass hierarchy between different phases of migration, confirming previous work showing that polarized light cues near the horizon at sunrise and sunset provide the primary calibration reference both in the beginning and at the end of migration.
Flores, Fernando Sebastián; Costa, Francisco Borges; Nava, Santiago; Diaz, Luiz Adrián; Labruna, Marcelo Bahia
Several tick-borne Rickettsia species are recognized human pathogens in Argentina. Here we evaluated rickettsial infection in ticks collected on passerine birds during 2011-2012 in two eco-regions of Argentina. The ticks were processed by molecular analysis through polymerase chain reaction (PCR) detection and DNA sequencing of fragments of two rickettsial genes, gltA and ompA. A total of 594 tick specimens (532 larvae and 62 nymphs), representing at least 4 species (Amblyomma tigrinum, Ixodes pararicinus, Haemaphysalis juxtakochi, Haemaphysalis leporispalustris), were evaluated. At least one A. tigrinum larva, collected on Coryphospingus cucullatus in Chaco Seco, was infected with Rickettsia parkeri, whereas at least 12 larvae and 1 nymph of I. pararicinus, collected from Troglodytes aedon, Turdus amaurochalinus, Turdus rufiventris, C. cucullatus and Zonotrichia capensis, were infected with an undescribed Rickettsia agent, genetically related to several rickettsial endosymbionts of ticks of the Ixodes ricinus complex. R. parkeri is a recognized human pathogen in several American countries including Argentina, where a recent study incriminated A. tigrinum as the potential vector of R. parkeri to humans. Birds could play an important role in dispersing R. parkeri-infected A. tigrinum ticks. Additionally, we report for the first time a rickettsial agent infecting I. pararicinus ticks.
Vyas, N.B.; Kuenzel, W.J.; Hill, E.F.; Romo, G.A.; Komaragiri, M.V.S.
Effects of a 14-day dietary exposure to an organophosphorus pesticide, acephate (acetylphosphoramidothioic acid O,S-dimethyl ester), were determined on cholinesterase activity in three regions (basal ganglia, hippocampus, and hypothalamus) of the white-throated sparrow, Zonotrichia albicollis, brain. All three regions experienced depressed cholinesterase activity between 0.5-2 ppm acephate. The regions exhibited cholinesterase recovery at 2-16 ppm acephate; however, cholinesterase activity dropped and showed no recovery at higher dietary levels (>16 ppm acephate). Evidence indicates that the recovery is initiated by the magnitude of depression, not the duration. In general, as acephate concentration increased, differences in ChE activity among brain regions decreased. Three terms are introduced to describe ChE response to acephate exposure: (1) ChE resistance threshold, (2) ChE compensation threshold, and (3) ChE depression threshold. It is hypothesized that adverse effects to birds in the field may occur at pesticide exposure levels customarily considered negligible.
Class, Alexandra M; Moore, Ignacio T
Tropical birds typically exhibit a 'slow pace of life' relative to higher latitude species. This is often manifested as slow development, low fecundity, and high survival. Following from this, it is predicted that tropical birds may be more likely to trade current reproductive effort to favor self-maintenance, thus supporting survival and future reproduction. To test this idea, we conducted two food supplementation experiments on tropical rufous-collared sparrows (Zonotrichia capensis) in the eastern Andes of Ecuador. In the first experiment, we food-supplemented pairs during the non-breeding life-history stage, and in the second experiment, we food-supplemented pairs that were provisioning fledglings. In both experiments, a larger proportion of food-supplemented birds exhibited pre-basic molt (replacement of feathers) than in a control group. To our knowledge, this is the first study to experimentally demonstrate that a food-supplemented bird invests extra resources into molt, a form of self-maintenance, and contrasts with the majority of food supplementation studies in high latitude birds that show they typically advance the initiation of, or extend the period of, reproduction. Our results are consistent with the syndrome of the slow pace of life in the tropics and support the concept of fundamental differences between temperate-zone and tropical birds.
Chizinski, Christopher J.; Peterson, Anna; Hanowski, JoAnn; Blinn, Charles R.; Vondracek, Bruce C.; Niemi, Gerald
We compared avian communities among three timber harvesting treatments in 45-m wide even-age riparian management zones (RMZs) placed between upland clearcuts and along one side of first- or second-order streams in northern Minnesota, USA. The RMZs had three treatments: (1) unharvested, (2) intermediate residual basal area (RBA) (targeted goal 11.5 m2/ha, realized 16.0 m2/ha), and (3) low RBA (targeted goal 5.7 m2/ha, realized 8.7 m2/ha). Surveys were conducted one year pre-harvest and three consecutive years post-harvest. There was no change in species richness, diversity, or total abundance associated with harvest but there were shifts in the types of birds within the community. In particular, White-throated Sparrows (Zonotrichia albicollis) and Chestnut-sided Warblers (Dendroica pensylvanica) increased while Ovenbirds (Seiurus aurocapilla) and Red-eyed Vireos (Vireo olivaceus) decreased. The decline of avian species associated with mature forest in the partially harvested treatments relative to controls indicates that maintaining an unharvested RMZ adjacent to an upland harvest may aid in maintaining avian species associated mature forest in Minnesota for at least three years post-harvest. However, our observations do not reflect reproductive success, which is an area for future research.
Kevin C. Hannah
Full Text Available The use of density to measure a species' responses to habitat change remains prevalent despite warnings that relying on such parameters can be misleading. We evaluated whether density was a useful surrogate of habitat quality for the White-throated Sparrow (Zonotrichia albicollis, an apparent habitat generalist, in a recently logged landscape near Calling Lake, Alberta, Canada. We detected significant differences in the territory density of birds among three distinct habitat types: interior forest, forest edges, and recent (4- to 6-yr-old clear-cuts. However, the observed patterns in territory density were not consistent with several indices of habitat quality. We found a consistent and marked gradient for indices such as nesting success (based on a reproductive index, pairing success, and the proportion of territories that successfully fledged young between interior forest sites and clear-cuts. Edge habitats, in which high relative density offset lower reproductive success, represented moderate-quality habitat for this species. Our results suggest that the continued use of density alone, without some measure of habitat quality, is insufficient if not misleading when evaluating response to habitat change. Our results have important implications for understanding the population dynamics of this species, which is often overlooked in population-level studies yet continues to experience long-term population declines over large portions of its breeding range.
Lenske, Ariel K; La, Van T
Animals can use acoustic signals to attract mates and defend territories. As a consequence, background noise that interferes with signal transmission has the potential to reduce fitness, especially in birds that rely on song. While much research on bird song has investigated vocal flexibility in response to urban noise, weather and other birds, the possibility of inter-class acoustic competition from anurans has not been previously studied. Using sound recordings from central Ontario wetlands, we tested if white-throated sparrows (Zonotrichia albicolis) make short-term changes to their singing behaviour in response to chorusing spring peepers (Pseudacris crucifer), as well as to car noise, wind and other bird vocalizations. White-throated sparrow songs that were sung during the spring peeper chorus were shorter with higher minimum frequencies and narrower bandwidths resulting in reduced frequency overlap. Additionally, sparrows were less likely to sing when car noise and the vocalizations of other birds were present. These patterns suggest that birds use multiple adjustment strategies. This is the first report to demonstrate that birds may alter their songs differentially in response to different sources of noise. This article is part of a Special Issue entitled: insert SI title.
Grozhik, Anya V; Horoszko, Christopher P; Horton, Brent M; Hu, Yuchen; Voisin, Dene A; Maney, Donna L
Behaviors associated with breeding are seasonally modulated in a variety of species. These changes in behavior are mediated by sex steroids, levels of which likewise vary with season. The effects of androgens on behaviors associated with breeding may in turn be partly mediated by the nonapeptides vasopressin (VP) and oxytocin (OT) in mammals, and vasotocin (VT) in birds. The effects of testosterone (T) on production of these neuropeptides have been well-studied; however, the regulation of VT receptors by T is not well understood. In this study, we investigated steroid-dependent regulation of VT receptor (VTR) mRNA in a seasonally breeding songbird, the white-throated sparrow (Zonotrichia albicollis). We focused on VTR subtypes that have been most strongly implicated in social behavior: V1a and oxytocin-like receptor (OTR). Using in situ hybridization, we show that T-treatment of non-breeding males altered V1a and OTR mRNA expression in several regions associated with seasonal reproductive behaviors. For example, T-treatment increased V1a mRNA expression in the medial preoptic area, bed nucleus of the stria terminalis, and ventromedial hypothalamus. T-treatment also affected both V1a and OTR mRNA expression in nuclei of the song system; some of these effects depended on the presence or absence of a chromosomal rearrangement that affects singing behavior, plasma T, and VT immunolabeling in this species. Overall, our results strengthen evidence that VT helps mediate the behavioral effects of T in songbirds, and suggest that the chromosomal rearrangement in this species may affect the sensitivity of the VT system to seasonal changes in T.
Astudillo, Viviana González; Hernández, Sonia M; Kistler, Whitney M; Boone, Shaun L; Lipp, Erin K; Shrestha, Sudip; Yabsley, Michael J
The prevalence of five avian haemoparasite groups was examined for effects on health and associations with extrinsic factors. Overall, 786 samples were examined from six sites in two Georgia (USA) watersheds, during breeding and non-breeding periods in 2010 and 2011. Among the four most commonly infected species, Haemoproteus prevalence was significantly higher in Northern Cardinals (Cardinalis cardinalis) compared to Indigo Buntings (Passerina cyanea) and Tufted Titmice (Baeolophus bicolor) while prevalence in White-throated Sparrows (Zonotrichia albicollis) was significantly higher than in Indigo Buntings. Higher prevalence of Plasmodium was noted in Tufted Titmice and Northern Cardinals. While Leucocytozoon prevalence was highest in White-throated Sparrows, Trypanosoma prevalence was highest in Tufted Titmice. Interesting differences in infection probabilities were noted between foraging guilds with Haemoproteus associated with low-middle level strata and birds in the middle-upper strata were more likely to be infected with Plasmodium and Trypanosoma. In contrast, ground-foraging birds were more likely to be infected with Leucocytozoon. Breeding season was correlated with higher polychromasia counts and higher prevalence of Haemoproteus, Plasmodium and Trypanosoma. In addition, prevalence of infection with certain haemoparasite genera and packed cell volume (PCV) were different among host species. Body mass index was inversely correlated with prevalence of microfilaria infection but positively related to Haemoproteus infection. However, we found no relationship between PCV or polychromasia levels with haemoparasite infection. Molecular characterization of 61 samples revealed 19 unique Haemoproteus (n = 7) and Plasmodium (n = 12) haplotypes with numerous new host records. No differences were noted in haplotype diversity among birds with different migratory behaviors or foraging heights, thus additional studies are needed that incorporate molecular analysis
Klich, M; Lankester, M W; Wu, K W
Birds that had migrated northward across Lake Superior were captured upon reaching landfall at Thunder Cape (48 degrees 18' N, 88 degrees 56' W) at the southwestern tip of the Sibley Peninsula, northwestern Ontario, from 9 May to 9 June 1995. Twenty-one of 530 birds examined (6 of 55 species) had a total of 34 ticks; 1 blue jay, Cyanocitta cristata, had a northern fowl mite, Ornithonyssus sylviarum (Canestrini & Fanzago). Four blacklegged tick, Ixodes scapularis Say, larvae were found on an American robin, Turdus migratorius, and 2 on a chipping sparrow, Spizella passerina. This tick was not found on small mammals at Thunder Cape. Twenty-six larvae and a nymph of the rabbit tick, Haemaphysalis leporispalustris (Packard) were found on 1 American robin, 2 Swainson's thrushes, Catharus ustulatus, 1 white-throated sparrow, Zonotrichia albicollis, 1 common yellowthroat, Geothlypis trichas, 1 blue jay, and 12 chipping sparrows. A nymph of H. chordeilis (Packard) occurred on 1 chipping sparrow. Results demonstrate that northward migrating birds transport larvae of I. scapularis to areas of Ontario where the tick does not appear to have become established in small mammal populations. Spring migrants may be more involved in the dispersal of I. scapularis larvae than previously thought. Cooler temperatures and shorter seasons experienced in the more northerly, continental parts of the established distribution of this tick may extend the life cycle, resulting in a predominance of larvae rather than nymphs being acquired by northward-bound birds in early spring. Consequently, the role of spring migrating birds in the northward spread of I. scapularis and of borreliosis should be reevaluated.
Price, Edwin R; Bauchinger, Ulf; Zajac, Daria M; Cerasale, David J; McFarlan, Jay T; Gerson, Alexander R; McWilliams, Scott R; Guglielmo, Christopher G
Seasonal adjustments to muscle size in migratory birds may result from preparatory physiological changes or responses to changed workloads. The mechanisms controlling these changes in size are poorly understood. We investigated some potential mediators of flight muscle size (myostatin and insulin-like growth factor, IGF1) in pectoralis muscles of wild wintering or migrating white-throated sparrows (Zonotrichia albicollis), captive white-throated sparrows that were photoperiod manipulated to be in a `wintering' or `migratory' (Zugunruhe) state, and captive European starlings (Sturnus vulgaris) that were either exercised for 2 weeks in a wind tunnel or untrained. Flight muscle size increased in photo-stimulated `migrants' and in exercised starlings. Acute exercise but not long-term training caused increased expression of IGF1, but neither caused a change in expression of myostatin or its metalloprotease activator TLL1. Photo-stimulated `migrant' sparrows demonstrated increased expression of both myostatin and IGF1, but wild sparrows exhibited no significant seasonal changes in expression of either myostatin or IGF1. Additionally, in both study species we describe several splice variants of myostatin that are shared with distantly related bird species. We demonstrate that their expression patterns are not different from those of the typical myostatin, suggesting that they have no functional importance and may be mistakes of the splicing machinery. We conclude that IGF1 is likely to be an important mediator of muscle phenotypic flexibility during acute exercise and during endogenous, seasonal preparation for migration. The role of myostatin is less clear, but its paradoxical increase in photo-stimulated `migrants' may indicate a role in seasonal adjustments of protein turnover.
Newman, Erica A; Eisen, Lars; Eisen, Rebecca J; Fedorova, Natalia; Hasty, Jeomhee M; Vaughn, Charles; Lane, Robert S
Although Borrelia burgdorferi sensu lato (s.l.) are found in a great diversity of vertebrates, most studies in North America have focused on the role of mammals as spirochete reservoir hosts. We investigated the roles of birds as hosts for subadult Ixodes pacificus ticks and potential reservoirs of the Lyme disease spirochete B. burgdorferi sensu stricto (s.s.) in northwestern California. Overall, 623 birds representing 53 species yielded 284 I. pacificus larvae and nymphs. We used generalized linear models and zero-inflated negative binomial models to determine associations of bird behaviors, taxonomic relationships and infestation by I. pacificus with borrelial infection in the birds. Infection status in birds was best explained by taxonomic order, number of infesting nymphs, sampling year, and log-transformed average body weight. Presence and counts of larvae and nymphs could be predicted by ground- or bark-foraging behavior and contact with dense oak woodland. Molecular analysis yielded the first reported detection of Borrelia bissettii in birds. Moreover, our data suggest that the Golden-crowned Sparrow (Zonotrichia atricapilla), a non-resident species, could be an important reservoir for B. burgdorferi s.s. Of 12 individual birds (9 species) that carried B. burgdorferi s.l.-infected larvae, no birds carried the same genospecies of B. burgdorferi s.l. in their blood as were present in the infected larvae removed from them. Possible reasons for this discrepancy are discussed. Our study is the first to explicitly incorporate both taxonomic relationships and behaviors as predictor variables to identify putative avian reservoirs of B. burgdorferi s.l. Our findings underscore the importance of bird behavior to explain local tick infestation and Borrelia infection in these animals, and suggest the potential for bird-mediated geographic spread of vector ticks and spirochetes in the far-western United States.
Erica A Newman
Full Text Available Although Borrelia burgdorferi sensu lato (s.l. are found in a great diversity of vertebrates, most studies in North America have focused on the role of mammals as spirochete reservoir hosts. We investigated the roles of birds as hosts for subadult Ixodes pacificus ticks and potential reservoirs of the Lyme disease spirochete B. burgdorferi sensu stricto (s.s. in northwestern California. Overall, 623 birds representing 53 species yielded 284 I. pacificus larvae and nymphs. We used generalized linear models and zero-inflated negative binomial models to determine associations of bird behaviors, taxonomic relationships and infestation by I. pacificus with borrelial infection in the birds. Infection status in birds was best explained by taxonomic order, number of infesting nymphs, sampling year, and log-transformed average body weight. Presence and counts of larvae and nymphs could be predicted by ground- or bark-foraging behavior and contact with dense oak woodland. Molecular analysis yielded the first reported detection of Borrelia bissettii in birds. Moreover, our data suggest that the Golden-crowned Sparrow (Zonotrichia atricapilla, a non-resident species, could be an important reservoir for B. burgdorferi s.s. Of 12 individual birds (9 species that carried B. burgdorferi s.l.-infected larvae, no birds carried the same genospecies of B. burgdorferi s.l. in their blood as were present in the infected larvae removed from them. Possible reasons for this discrepancy are discussed. Our study is the first to explicitly incorporate both taxonomic relationships and behaviors as predictor variables to identify putative avian reservoirs of B. burgdorferi s.l. Our findings underscore the importance of bird behavior to explain local tick infestation and Borrelia infection in these animals, and suggest the potential for bird-mediated geographic spread of vector ticks and spirochetes in the far-western United States.
Gonser Rusty A
Full Text Available Abstract Background The genomics era has produced an arsenal of resources from sequenced organisms allowing researchers to target species that do not have comparable mapping and sequence information. These new "non-model" organisms offer unique opportunities to examine environmental effects on genomic patterns and processes. Here we use comparative mapping as a first step in characterizing the genome organization of a novel animal model, the white-throated sparrow (Zonotrichia albicollis, which occurs as white or tan morphs that exhibit alternative behaviors and physiology. Morph is determined by the presence or absence of a complex chromosomal rearrangement. This species is an ideal model for behavioral genomics because the association between genotype and phenotype is absolute, making it possible to identify the genomic bases of phenotypic variation. Findings We initiated a genomic study in this species by characterizing the white-throated sparrow BAC library via filter hybridization with overgo probes designed for the chicken, turkey, and zebra finch. Cross-species hybridization resulted in 640 positive sparrow BACs assigned to 77 chicken loci across almost all macro-and microchromosomes, with a focus on the chromosomes associated with morph. Out of 216 overgos, 36% of the probes hybridized successfully, with an average number of 3.0 positive sparrow BACs per overgo. Conclusions These data will be utilized for determining chromosomal architecture and for fine-scale mapping of candidate genes associated with phenotypic differences. Our research confirms the utility of interspecies hybridization for developing comparative maps in other non-model organisms.
Seewagen, Chad L; Guglielmo, Christopher G
Most studies of lean mass dynamics in free-living passerine birds have focused on Old World species at geographical barriers where they are challenged to make the longest non-stop flight of their migration. We examined lean mass variation in New World passerines in an area where the distribution of stopover habitat does not require flights to exceed more than a few hours and most migrants stop flying well before fat stores near exhaustion. We used either quantitative magnetic resonance (QMR) analysis or a morphometric model to measure or estimate, respectively, the fat and lean body mass of migrants during stopovers in New York, USA. With these data, we examined (1) variance in total body mass explained by lean body mass, (2) hourly rates of fat and lean body mass change in single-capture birds, and (3) net changes in fat and lean mass in recaptured birds. Lean mass contributed to 50% of the variation in total body mass among white-throated sparrows Zonotrichia albicollis and hermit thrushes Catharus guttatus. Lean mass of refueling gray catbirds Dumetella carolinensis and white-throated sparrows, respectively, increased 1.123 and 0.320 g h(-1). Lean mass of ovenbirds Seiurus aurocapillus accounted for an estimated 33-40% of hourly gains in total body mass. On average 35% of the total mass gained among recaptured birds was lean mass. Substantial changes in passerine lean mass are not limited to times when birds are forced to make long, non-stop flights across barriers. Protein usage during migration is common across broad taxonomic groups, migration systems, and migration strategies.
Danner, J E; Fleischer, R C; Danner, R M; Moore, I T
Female preference for local cultural traits has been proposed as a barrier to breeding among animal populations. As such, several studies have found correlations between male bird song dialects and population genetics over relatively large distances. To investigate whether female choice for local dialects could act as a barrier to breeding between nearby and contiguous populations, we tested whether variation in male song dialects explains genetic structure among eight populations of rufous-collared sparrows (Zonotrichia capensis) in Ecuador. Our study sites lay along a transect, and adjacent study sites were separated by approximately 25 km, an order of magnitude less than previously examined for this and most other species. This transect crossed an Andean ridge and through the Quijos River Valley, both of which may be barriers to gene flow. Using a variance partitioning approach, we show that song dialect is important in explaining population genetics, independent of the geographic variables: distance, the river valley and the Andean Ridge. This result is consistent with the hypothesis that song acts as a barrier to breeding among populations in close proximity. In addition, songs of contiguous populations differed by the same degree or more than between two populations previously shown to exhibit female preference for local dialect, suggesting that birds from these populations would also breed preferentially with locals. As expected, all geographic variables (distance, the river valley and the Andean Ridge) also predicted population genetic structure. Our results have important implications for the understanding whether, and at what spatial scale, culture can affect population divergence. © 2017 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2017 European Society For Evolutionary Biology.
Barceló, Gonzalo; Ríos, Juan Manuel; Maldonado, Karin; Sabat, Pablo
Seed-eating birds have a diet of high nutritional value; however, they must cope with plant secondary metabolites (PSM). We postulated that the detoxification capacity of birds is associated with a metabolic cost, given that the organs responsible for detoxification significantly contribute to energetic metabolism. We used an experimental approach to assess the effects of phenol-enriched diets on two passerines with different feeding habits: the omnivorous rufous-collared sparrow (Zonotrichia capensis) and the granivorous common diuca-finch (Diuca diuca). The birds were fed with one of three diets: control diet, supplemented with tannic acid, or supplemented with Opuntia ficus-indica phenolic extract (a common food of the sparrow but not the finch). After 5 weeks of exposure to the diets, we measured basal metabolic rates (BMR), energy intake, glucuronic acid output and digestive and kidney structure. In both species, detoxification capacity expressed as glucuronic acid output was higher in individuals consuming phenol-enriched diets compared to the control diet. However, whereas sparrows increase energy intake and intestinal mass when feeding on phenol-enriched diets, finches had lower intestinal mass and energy intake remains stable. Furthermore, sparrows had higher BMR on phenol-enriched diets compared to the control group, whereas in the finches BMR remains unchanged. Interspecific differences in response to phenols intake may be determined by the dietary habits of these species. While both species can feed on moderate phenolic diets for 5 weeks, energy costs may differ due to different responses in food intake and organ structure to counteract the effects of PSM intake.
Moore, Ignacio T; Bentley, George E; Wotus, Cheryl; Wingfield, John C
Timing of seasonal reproduction in high latitude vertebrates is generally regulated by photoperiodic cues. Increasing day length in the spring is associated with changes in the brain that are responsible for mediating reproductive activities. A primary example of this is the increased content of gonadotropin-releasing hormone (GnRH) in the preoptic area of the hypothalamus in birds as they enter the spring breeding season. Increased GnRH activity stimulates the release of luteinizing hormone and follicle-stimulating hormone from the anterior pituitary. These gonadotropins induce growth of the gonads and release of sex steroids which act on the brain to mediate reproductive behaviors. By contrast, seasonal breeding in the tropics can occur in the absence of significant changes in photoperiod. To our knowledge, no studies have investigated whether seasonal breeding in free-living tropical vertebrates is associated with seasonal changes in the GnRH system. We studied two populations of rufous-collared sparrows (Zonotrichia capensis) at the equator, separated by only 25 km, but with asynchronous reproductive phenologies associated with local climate and independent of photoperiodic cues. We collected brains and measured GnRH immunoreactivity (GnRH-ir) during each population's breeding and non-breeding periods. Breeding males had larger, but not more, GnRH-ir cells than non-breeding birds. The plasticity of the GnRH system was associated with local climate, such that the two populations exhibited asynchronous changes in GnRH-ir despite experiencing identical photoperiod conditions. Our results demonstrate that tropical birds can exhibit neural changes similar to those exhibited in higher latitude birds. However, these tropical populations appear to be using supplementary cues (e.g., rainfall, temperature, food availability) in a similar way to higher latitude species using an initial predictive cue (photoperiod). These results raise questions about the evolution of
Miller Alden H.
Full Text Available Para el estudio de los ciclos reproductivos de las aves cerca al ecuador se seleccionó el Gorrión (Zonotrichia capensis teniendo en cuenta que se han realizado estudios intensivos en especies próximas que habitan el hemisferio norte. Se escogió como estación de trabajo, el sitio denominado Mares localizado en la cima de la Cordillera Occidental sobre la carretera que conduce de Cali a Buenaventura. Mediante trabajos de anillado, instalación de trampas para captura de las aves, realización de laparotomías y observación constante. se ha llegado a las siguientes conclusiones preliminares: a Que las aves cerca del ecuador tienen como en otras latitudes periodos o ciclos de reproducción, aunque la especie en conjunto pueda estar anidando prácticamente durante todo el año. b Que los machos están en condiciones fisiológicas para reproducirse a los cinco meses de edad y que con seguridad algunos permanecen en condiciones de reproducción durante cuatro meses continuos; además que las hembras anidan a los cinco meses de edad. c Que estas aves tienen una marcada resistencia contra las infecciones que podrían sobrevenirles por el empleo de instrumental quirúrgico sin previa desinfección, usado en las intervenciones. Algunos individuos fueron operados hasta tres veces y tan solo se sabe de uno que murió, no debido a infección sino a una alta dosis de anestesia. A partir del ocho de febrero del presente año, se han anillado ciento veinte (120 individuos en un área aproximada de dos hectáreas, y se ha coleccionado material adicional en la vecindad de la estación de estudio, el cual se preserva para futuros estudios comparativos. Para el estudio de los ciclos reproductivos de las aves cerca al ecuador se seleccionó el Gorrión (Zonotrichia capensis teniendo en cuenta que se han realizado estudios intensivos en especies próximas que habitan el hemisferio norte. Se escogió como estación de trabajo, el sitio denominado Mares
Arnberg, Nina N.
Stable social organization in a wide variety of organisms has been linked to kinship, which can minimize conflict due to the indirect fitness benefits from cooperating with relatives. In birds, kin selection has been mostly studied in the context of reproduction or in species that are social year round. Many birds however are migratory and the role of kinship in the winter societies of these species is virtually unexplored. A previous study detected striking social complexity and stability in wintering populations of migratory golden-crowned sparrows (Zonotrichia atricapilla)---individuals repeatedly form close associations with the same social partners, including across multiple winters. In chapter one I test the possibility that kinship might be involved in these close and stable social affiliations. I examine the relationship between kinship and social structure for two of the consecutive wintering seasons from the previous study. I found no evidence that social structure was influenced by kinship---relatedness between most pairs of individuals was at most that of first cousins (and mostly far lower) and Mantel tests revealed no relationship between kinship and pairwise interaction frequency. Kinship also failed to predict social structure in more fine-grained analyses, including analyses of each sex separately (in the event that sex-biased migration might limit kin selection to one sex) and separate analyses for each social community. The complex winter societies of golden-crowned sparrows appear to be based on cooperative benefits unrelated to kin selection. Although the complex social structure detected in wintering golden-crowned sparrows is not predicted by kinship, genetic variation may play a role in variation of winter social traits. In chapter two, I investigate the genetic causes of variation in fitness-related traits in a winter population of golden-crowned sparrows. Individuals show great variation in morphological and behavioral traits that may play