A chromosome-level genome assembly of a free-living white-crowned sparrow (Zonotrichia leucophrys gambelii).

The white-crowned sparrow, Zonotrichia leucophrys, is a passerine bird with a wide distribution and it is extensively adapted to environmental changes. It has historically acted as a model species in studies on avian ecology, physiology and behaviour. Here, we present a high-quality chromosome-level genome of Zonotrichia leucophrys using PacBio and OmniC sequencing data. Gene models were constructed by combining RNA-seq and Iso-seq data from liver, hypothalamus, and ovary. In total a 1,123,996,003 bp genome was generated, including 31 chromosomes assembled in complete scaffolds along with other, unplaced scaffolds. This high-quality genome assembly offers an important genomic resource for the research community using the white-crowned sparrow as a model for understanding avian genome biology and development, and provides a genomic basis for future studies, both fundamental and applied.

Blood parasites of passerines in the Brazilian Pampas and their implications for a potential population supplementation program for the endangered Yellow Cardinal (Gubernatrix cristata).

Espinilho savanna ("seasonal steppe savanna") is a unique vegetation formation of the Pampas biome that is found near the tri-border of Brazil, Uruguay, and Argentina. The Yellow Cardinal (Gubernatrix cristata) is a flagship species of this ecosystem, but it is classified as "critically endangered" in Brazil due to habitat loss and poaching for the illegal trade. Population supplementation through the release of individuals that were captive-bred or apprehended by authorities from the illegal trade has been considered as a conservation strategy for this species; however, the risk of pathogen introduction is a critical concern. We used microscopy and molecular methods to investigate the occurrence of blood parasites in wild passerines (n = 64, including three Yellow Cardinals) at Espinilho State Park, Rio Grande do Sul, Brazil, and in captive Yellow Cardinals (n = 30) at three facilities in Brazil. Haemosporidian parasites were detected in the blood smears of 10.9% of the wild passerines, comprising the morphospecies Haemoproteus erythrogravidus in Rufous-collared Sparrow (Zonotrichia capensis), H. quiscalus in Grayish Baywing (Agelaioides badius), and H. tyranni in Great Kiskadee (Pitangus sulphuratus); these are the southernmost records for these morphospecies and their first record for the Pampas biome. No haemosporidian parasites were detected in the blood smears of the Yellow Cardinals, wild or captive. Microfilariae were detected in the blood smears of 14.1% of the wild passerines, including all wild Yellow Cardinals, and in 43.3% of captive Yellow Cardinals. Trypanosoma sp. was detected in the blood smear of one captive Yellow Cardinal. Nested PCR and gene sequencing of the cyt-b gene of Haemoproteus/Plasmodium was used to test a subset of wild passerines and captive Yellow Cardinals, allowing for the molecular barcoding of H. quiscalus lineage AGEBAD04 and H. tyranni lineage PITSUL01; additionally, DNA identical to that of lineage PITSUL01 was detected in the blood of one captive Yellow Cardinal. This study provides valuable data to support the conservation management of the Yellow Cardinal and other threatened passerines from the Pampas and highlights the need for further studies on the epidemiology and pathology of filarioid worms and trypanosomes in passerines from this biome.

Hypothalamic expression of GnRH-I and GnIH in the Eurasian tree sparrow over a single long day.

Seasonal reproductive cycles of most birds are regulated by photoperiod via neuroendocrine control. The present study aims to investigate the role of a single long day in triggering hypothalamic expressions of GnRH-I and GnIH in the Eurasian tree sparrow (Passer montanus). Sparrows were divided into two groups (n = 24 each) and pre-treated under short days (9L: 15D) for 4 days. On the fifth day, one group was exposed to long day (14L: 10D), while other was continued under short day for another 1 day. Birds of both the groups were sacrificed and perfused on fifth day at different time points, i.e., ZT 14, ZT 16 and ZT 18 and the expressions of GnRH-I and GnIH mRNAs and peptides were studied using real-time PCR and immunohistochemistry, respectively. In addition, testicular size was measured to know testicular development. Observations revealed that birds exposed to a single long day (14L: 10D) showed an increase in hypothalamic expressions of GnRH-I mRNA and peptide and decrease in levels of GnIH mRNA only at ZT 16 and ZT 18 with no significant change in GnIH peptide. However, no significant change in GnRH-I or GnIH expression was observed at any time point under short day and birds maintained high and low expression levels of GnIH and GnRH-I, respectively. Our results clearly indicate that the photoperiodic response system of sparrow is highly sensitive to light and responds even to single long day. Furthermore, they suggest that the GnRH-I and GnIH are expressed in the hypothalamus of tree sparrow in an anti-phasic manner and switching over of their expression occurs at late hours of exposure of birds to single long day.

[Experimental research on characteristics of temperature field distribution of mild moxibustion and sparrow-pecking moxibustion].

OBJECTIVE: To explore the temperature field distribution and variation rules during treatment with mild moxibustion and sparrow-pecking moxibustion of TCM. METHODS: Six healthy subjects were selected. Mild moxibustion and sparrow-pecking moxibustion were exerted at Zusanli (ST 36) respectively, for 25 min. Using infrared thermal imaging instrument, the temperature field distribution was measured during moxibustion at Zusanli (ST 36). The simulated thermometer was adopted to measure the temperature field distribution during moxibustion at the imitated cortex. At 20 min of mild moxibustion and sparrow-pecking moxibustion, the temperature field distribution generated by moxibustion was observed at the imitated cortex and Zusanli (ST 36) separately. The temperature values were collected at the sites 0.7, 2.1 and 3.5 cm far from the center of the moxibustion-exerted places successively, and then the characteristics of temperature field distribution and variation rules were compared between different moxibustion methods at the imitated cortex and Zusanli (ST 36). RESULTS: At 20 min of mild moxibustion and sparrow-pecking moxibustion at Zusanli (ST 36), the temperature field distribution focused on the center of moxibustion-exerted site and the temperature was reduced to all directions and illustrated as a curved surface graph, whereas, the temperature field distribution at the imitated cortex was consistent with that at Zusanli (ST 36). With mild moxibustion, the temperature field was distributed uniformly along the longitudinal temperature gradient; whereas, with sparrow-pecking moxibustion, the longitudinal temperature of the temperature field was greatly different, in which, the maximum temperature and the average temperature were higher than those with mild moxibustion respectively and the first time up to the peak value of sparrow-pecking moxibustion was shorter than that with mild moxibustion. The thermal transfer was presented at the non-moxibustion exerted areas during the moxibustion experiment at Zusanli (ST 36). CONCLUSION: A distance feature is presented in the temperature field measured by simulated thermometer and generated under suspension moxibustion at Zusanli (ST 36). The warm stimulation effect of sparrow-pecking moxibustion is much more obvious at the moxibustion-exerted center as compared with mild moxibustion and the area of warm stimulation generated by sparrow-pecking moxibustion is more concentrated as compared with mild moxibustion. The radiation energy produced by suspension moxibustion is scattered and attenuated in skin tissue, resulting in a certain temperature gradient in the temperature field. The warm stimulation generated at skin surface by moxibustion has a warming-dredging effect.

TA-65 does not increase telomere length during post-natal development in house sparrow chicks (Passer domesticus).

Telomeres, protective caps at the end of chromosomes, are often positively related to lifespan and are thought to be an important mechanism of organismal aging. To better understand the casual relationships between telomere length and longevity, it is essential to be able to experimentally manipulate telomere dynamics (length and loss rate). Previous studies suggest that exposure to TA-65, an extract from the Chinese root Astragalus membranaceus, activates telomerase, lengthens telomeres, increases the growth of keratin-based structures, and boosts the immune system in adults. However, telomere loss is expected to be greatest during early life but whether TA-65 has similar effects during this life stage is currently unknown. Here, we experimentally exposed free-living house sparrow (Passer domesticus) chicks to TA-65 during post-natal development and examined the effects on telomere length and loss, growth of keratin-based structures, and a measure of cellular immunity. Contrary to expectation, the growth of keratin-based structures was reduced in TA-65 chicks and in the second year of the study, chicks exposed to TA-65 experienced more telomere loss than controls. Thus, the effects of TA-65 on telomeres and keratin-based structures differ across life stages and future research will be necessary to determine the mechanisms underlying these age-specific effects.

Urban environment alter the timing of progression of testicular recrudescence in tree sparrow (Passer montanus).

Urbanization is a rapidly growing phenomenon that affects wildlife. Laboratory studies show the effects of night light on the physiology of the organisms. Limited studies have been conducted on birds in their natural habitat. Here, we studied the effects of the urban environment on reproduction-linked phenomenon and molecules involved in the regulation of seasonal breeding. Birds (N=5/time/site) were procured from urban and rural sites at specific times, i.e., in March (stimulatory phase), June (reproductive phase), September (refractory phase), and December (sensitive phase) of 2018. Immediately after procurement, birds were brought to the laboratory. Bodyweight, bill color, molt in body feathers, and testes size were recorded. The next day, all the birds were sacrificed in the middle of the day. Blood was collected and serum was used for ELISA of corticosterone, triiodothyronine (T3), and thyroxine (T4). mRNA levels of thyroid-stimulating hormone-ß (Tshß), type 2 deiodinase (Dio2), type 3 deiodinase (Dio3), gonadotropin-releasing hormone (GnRh), and gonadotropin inhibitory hormone (GnIh) were measured in hypothalamic tissue. Urban birds showed higher levels of corticosterone during the stimulatory phase. There was a delay in the initiation of testicular growth in urban birds and it was supported by reduced levels of T3 in blood plasma and relatively lower transcription of Dio2 and GnRH mRNA in urban birds. Our findings suggest that the urban environment delays the timing of reproduction in birds and could be the consequence of local environmental conditions.

Experimental research on characteristics of temperature field distribution of mild moxibustion and sparrow-pecking moxibustion / 中国针灸

OBJECTIVE@#To explore the temperature field distribution and variation rules during treatment with mild moxibustion and sparrow-pecking moxibustion of TCM.@*METHODS@#Six healthy subjects were selected. Mild moxibustion and sparrow-pecking moxibustion were exerted at Zusanli (ST 36) respectively, for 25 min. Using infrared thermal imaging instrument, the temperature field distribution was measured during moxibustion at Zusanli (ST 36). The simulated thermometer was adopted to measure the temperature field distribution during moxibustion at the imitated cortex. At 20 min of mild moxibustion and sparrow-pecking moxibustion, the temperature field distribution generated by moxibustion was observed at the imitated cortex and Zusanli (ST 36) separately. The temperature values were collected at the sites 0.7, 2.1 and 3.5 cm far from the center of the moxibustion-exerted places successively, and then the characteristics of temperature field distribution and variation rules were compared between different moxibustion methods at the imitated cortex and Zusanli (ST 36).@*RESULTS@#At 20 min of mild moxibustion and sparrow-pecking moxibustion at Zusanli (ST 36), the temperature field distribution focused on the center of moxibustion-exerted site and the temperature was reduced to all directions and illustrated as a curved surface graph, whereas, the temperature field distribution at the imitated cortex was consistent with that at Zusanli (ST 36). With mild moxibustion, the temperature field was distributed uniformly along the longitudinal temperature gradient; whereas, with sparrow-pecking moxibustion, the longitudinal temperature of the temperature field was greatly different, in which, the maximum temperature and the average temperature were higher than those with mild moxibustion respectively and the first time up to the peak value of sparrow-pecking moxibustion was shorter than that with mild moxibustion. The thermal transfer was presented at the non-moxibustion exerted areas during the moxibustion experiment at Zusanli (ST 36).@*CONCLUSION@#A distance feature is presented in the temperature field measured by simulated thermometer and generated under suspension moxibustion at Zusanli (ST 36). The warm stimulation effect of sparrow-pecking moxibustion is much more obvious at the moxibustion-exerted center as compared with mild moxibustion and the area of warm stimulation generated by sparrow-pecking moxibustion is more concentrated as compared with mild moxibustion. The radiation energy produced by suspension moxibustion is scattered and attenuated in skin tissue, resulting in a certain temperature gradient in the temperature field. The warm stimulation generated at skin surface by moxibustion has a warming-dredging effect.

Sparrows use a medicinal herb to defend against parasites and increase offspring condition.

The incorporation of aromatic plants into nests by birds is suspected to constitute an example of preventative medicine use, whereby the phytochemical compounds within plants reduce infestation by parasites and increase offspring condition [1,2]. In China, russet sparrows (Passer cinnamomeus) incorporate wormwood (Artemisia verlotorum) leaves into their nests around the same time that local people hang wormwood from their doors as a traditional custom during the Dragon Boat Festival. The belief that this behaviour confers protection against ill health [3] is supported by the description of anti-parasite compounds in wormwood [4]. It has been suggested that the incorporation of fresh wormwood leaves into nests may serve a similar function for sparrows. Here we show that sparrows choose nest location and resupply established nests with fresh wormwood leaves using olfactory cues, that nests containing wormwood leaves have lower ectoparasite loads, and that nests with more wormwood leaves produce heavier chicks. Our results indicate that sparrows use wormwood as a preventative medicine to control ectoparasites and improve the body mass of their offspring.

Season dependent effects of urban environment on circadian clock of tree sparrow (Passer montanus).

Great efforts have been made recently to understand the effect(s) of urban environments on the circadian and seasonal physiology of wild animals, but the mechanisms involved remain largely unknown. Most laboratory studies and a few studies on animals in the wild suggest alterations occur in the physiological functions of organisms in urban habitats. Here, we addressed the effects of the interaction of seasons and urban environments on clock gene expression in three tissues of tree sparrows (Passer montanus). Tree sparrows (N = 30 per site per time of year) were procured from rural and urban habitats during periods corresponding to their three physiological states, i.e., June (longest photoperiod; reproductive phase), September (equinox photoperiod; refractory phase), and December (shortest photoperiod; sensitive phase). Birds (N = 5 per time per site per month) were sampled at six time points; ZT1, ZT5, ZT9, ZT13, ZT17, and ZT21 (ZT0 = sunrise time) and clock gene expression in the hypothalamus, pineal gland, and retina was studied. Our results show that there is persistence of the circadian clock in both rural and urban birds throughout the year. In urban birds Bmal1, Npas2, Per2, and Cry1 acrophases were advanced, compared to rural birds, while Clock acrophase was delayed, depending on the tissue and time of year. This difference could be because of changes in the availability, duration, and intensity of sunlight during different times of the year and/or differential photoreceptor sensitivities, differential physiological states, or a combination of all these factors. These important results reveal, for the first time in any species, season-dependent effects of an urban environment on the molecular machinery of the circadian clock.

Concurrent changes in photoperiod-induced seasonal phenotypes and hypothalamic CART peptide-containing systems in night-migratory redheaded buntings.

This study tested the hypothesis whether hypothalamic cocaine-and amphetamine-regulated transcript (CART)-containing systems were involved in photoperiod-induced responses associated with spring migration (hyperphagia and weight gain) and reproduction (gonadal maturation) in migratory songbirds. We specifically chose CART to examine neural mechanism(s) underlying photoperiod-induced responses, since it is a potent anorectic neuropeptide and involved in the regulation of changes in the body mass and reproduction in mammals. We first studied the distribution of CART-immunoreactivity in the hypothalamus of migratory redheaded buntings (Emberiza bruniceps). CART-immunoreactive neurons were found extensively distributed in the preoptic, lateral hypothalamic (LHN), anterior hypothalamic (AN), suprachiasmatic (SCN), paraventricular (PVN), dorsomedialis hypothalami (DMN), inferior hypothalamic (IH), and infundibular (IN) nuclei. Then, we correlated hypothalamic CART-immunoreactivity in buntings with photostimulated seasonal states, particularly winter non-migratory/non-breeding (NMB) state under short days, and spring premigratory/pre-breeding (PMB) and migratory/breeding (MB) states under long days. There were significantly increased CART-immunoreactive cells, and percent fluorescent area of CART-immunoreactivity was significantly increased in all mapped hypothalamic areas, except the SCN, PVN, AN, and DMN in photostimulated PMB and MB states, as compared to the non-stimulated NMB state. In particular, CART was richly expressed in the medial preoptic nucleus, LHN, IH and IN during MB state in which buntings showed reduced food intake and increased night-time activity. These results suggest that changes in the activity of the CART-containing system in different brain regions were associated with heightened energy needs of the photoperiod-induced seasonal responses during spring migration and reproduction in migratory songbirds.

Hypothalamic-Pituitary-Thyroid Axis Crosstalk With the Hypothalamic-Pituitary-Gonadal Axis and Metabolic Regulation in the Eurasian Tree Sparrow During Mating and Non-mating Periods.

Reproduction is an energetically costly phenomenon. Therefore, to optimize reproductive success, male birds invest enough energetic resources for maintaining well-developed testes. The hypothalamic-pituitary-thyroid (HPT) axis in birds can crosstalk with the hypothalamic-pituitary-gonadal (HPG) axis, thus orchestrating both the reproduction and metabolism. However, until now, how the free-living birds timely optimize both the energy metabolism and reproduction via HPT-axis is not understood. To uncover this physiological mechanism, we investigated the relationships among body mass, testis size, plasma hormones including thyroid-stimulating hormone (TSH), thyroxine (T4), triiodothyronine (T3), metabolites including glucose (Glu), triglyceride (TG), total cholesterol (TC), uric acid (UA), diencephalon mRNA expressions of type 2 (Dio2) and 3 (Dio3) iodothyronine deiodinase enzymes, thyrotropin-releasing hormone (TRH), thyroid-stimulating hormone (TSH), gonadotropin-releasing hormone I (GnRH-I), and gonadotropin-inhibitory hormone (GnIH) in a male Eurasian tree sparrow (ETS, Passer montanus). We found significantly larger testis size; elevated diencephalon Dio2 and TRH mRNA expressions, plasma T3, and UA levels; and significantly lowered Glu, TG, and TC levels during mating relative to the non-mating stages in male ETSs. However, Dio3, TSH, GnRH-I, and GnIH mRNA expression did not vary with the stage. Furthermore, life-history stage dependent variation in plasma T3 had both direct effects on the available energy substrates and indirect effects on body mass and testis size, indicating a complex regulation of metabolic pathways through the HPT- and HPG-axes. The identified differences and relationships in mRNA expression, plasma T3 and metabolites, and testis size in male ETSs contribute to our understanding how free-living birds adjust their molecular, endocrinal, and biochemical features to orchestrate their reproductive physiology and metabolism for the maintenance of well-developed testes.

Time course of photo-induced Egr-1 expression in the hypothalamus of a seasonally breeding songbird.

Many seasonally-breeding species use daylength to time reproduction. Light-induced release of progonadal hormones involves a complex cascade of responses both inside and outside the brain. In this study, we used induction of early growth response 1 (Egr-1), the protein product of an immediate early gene, to evaluate the time course of such responses in male white-throated sparrows (Zonotrichia albicollis) exposed to a single long day. Induction of Egr-1 in the pars tuberalis began ∼11 h after dawn. This response was followed ∼6 h later by dramatic induction in the tuberal hypothalamus, including in the ependymal cells lining the third ventricle. At approximately the same time, Egr-1 was induced in dopaminergic and vasoactive intestinal peptide neurons in the tuberal hypothalamus and in dopaminergic neurons of the premammillary nucleus. We noted no induction in gonadotropin-releasing hormone (GnRH) neurons until 2 h after dawn the following morning. Overall, our results indicate that Egr-1 responses in GnRH neurons occur rather late during photostimulation, compared with responses in other cell populations, and that such induction may reflect new synthesis related to GnRH depletion rather than stimulation by light cues.

Captivity alters neuroendocrine regulators of stress and reproduction in the hypothalamus in response to acute stress.

Wild animals are brought into captivity for many reasons. However, unlike laboratory-bred animals, wild caught animals often respond to the dramatic shift in their environment with physiological changes in the stress and reproductive pathways. Using wild-caught male and female house sparrows (Passer domesticus) we examined how time in captivity affects the expression of reproductive and stress-associated genes in the brain, specifically, the hypothalamus. We quantified relative mRNA expression of a neurohormone involved in the stress response (corticotropin releasing hormone [CRH]), a hypothalamic inhibitor of reproduction (gonadotropin inhibitory hormone [GnIH]), and the glucocorticoid receptor (GR), which is important in terminating the stress response. To understand potential shifts at the cellular level, we also examined the presence of hypothalamic GnIH (GnIH-ir) using immunohistochemistry. We hypothesized that expression of these genes and the abundance of cells immunoreactive for GnIH would change in response to time in captivity as compared to free-living individuals. We found that GR mRNA expression and GnIH-ir cell abundance increased after 24 and 45 days in captivity, as compared to wild-caught birds. At 66 days in captivity, GR expression and GnIH cell abundance did not differ from wild-caught birds, suggesting birds had acclimated to captivity. Evaluation of CRH and GnIH mRNA expression yielded similar trends, though they were not statistically significant. In addition, although neuroendocrine factors appeared to acclimate to captivity, a previous study indicated that corticosterone release and immune responses of these same birds did not acclimate to captivity, suggesting that neuroendocrine endpoints may adapt more rapidly to captivity than downstream physiological measures. These data expand our understanding of the physiological shifts occurring when wild animals are brought into captivity.

Transcriptome analysis indicates a broad range of toxic effects of Deepwater Horizon oil on Seaside Sparrows.

In marine species, the transcriptomic response to Deepwater Horizon (DWH) oil implicated many biochemical pathways, with corresponding adverse outcomes on organ development and physiological performance. Terrestrial organisms differ in their mechanisms of exposure to polycyclic aromatic hydrocarbons (PAHs) and their physiological challenges, and may reveal either distinct effects of oil on biochemical pathways or the generality of the responses to oil shown in marine species. Using a cross-species hybridization microarray approach, we investigated the transcriptomic response in the liver of Seaside Sparrows (Ammospiza maritima) exposed to DWH oil compared with birds from a control site. Our analysis identified 295 genes differentially expressed between birds exposed to oil and controls. Gene ontology (GO) and canonical pathway analysis suggested that the identified genes were involved in a coordinated response that promoted hepatocellular proliferation and liver regeneration while inhibiting apoptosis, necrosis, and liver steatosis. Exposure to oil also altered the expression of genes regulating energy homeostasis, including carbohydrate metabolism and gluconeogenesis, and the biosynthesis, transport and metabolism of lipids. These results provide a molecular mechanism for the long-standing observation of hepatic hypertrophy and altered lipid biosynthesis and transport in birds exposed to crude oil. Several of the activated pathways and pathological outcomes shown here overlap with the ones altered in fish species upon exposure to oil. Overall, our study shows that the path of oil contamination from the marine system into salt marshes can lead to similar responses in terrestrial birds to those described in marine organisms, suggesting similar adverse outcomes and shared machinery for detoxification.

Effect of urban environment on pineal machinery and clock genes expression of tree sparrow (Passer montanus).

Increasing urbanisation is altering the physiology of wild animals and the mechanisms involved are largely unknown. We hypothesised that altering the physiology of urban organisms is due to the effect of extra light at night on the circadian clock by modulating the expression of pineal machinery and clock genes. Two experiments were performed. In Experiment 1, immediately after being procured from their respective sites (urban and rural sites), birds were released individually in LLdim light conditions. Circadian rhythm period, activity duration, and total activity count were calculated and did not differ between urban and rural birds. In Experiment 2, birds (from urban and rural habitats) were sampled at six time points at regular 4-h intervals, beginning 1 h after sunrise. We measured daily variations in plasma melatonin levels. We also analysed the expression levels of Aanat, Mel1A and Mel1B as an indicator of melatonin biosynthesis and action machinery. Clock and clock-controlled genes (Bmal1, Clock, Per2, Per3, Cry1 and Npas2) were studied in the hypothalamus, the pineal gland, and retina to investigate the effects of urban habitats on the circadian clock. Our results show that there is a lower expression of Aanat in the pineal gland and relatively low plasma melatonin levels in urban birds. Further, clock genes are also differentially expressed in all three central tissues of urban birds. We propose that alterations in the melatonin biosynthesis machinery and the expression of clock genes could result in miscalculations in the internal timing of the organism, with environmental timings leading to altered physiology in urban wild animals.

Daily expression of clock genes in central and peripheral tissues of tree sparrow (Passer montanus).

Almost all organisms live in a fluctuating environment. To achieve synchrony with the fluctuating environment, organisms have evolved with time-tracking mechanism commonly known as biological clocks. This circadian clock machinery has been identified in almost all cells of vertebrates and categorized as central and peripheral clocks. In birds, three independent circadian clocks reside within the nervous tissues in the hypothalamus, pineal and retina, which interact with each other and produce circadian time at a functional level. There is limited knowledge available of the molecular clockwork, and of integration between central and peripheral clocks in birds. Here, we studied daily expression of canonical clock genes (Bmal1, Clock, Per2, Per3, Cry1 and Cry2) and clock-controlled gene (Npas2) in all three central tissues (hypothalamus, pineal and retina) and in peripheral tissues (liver, intestine and muscle). Wild caught adult male tree sparrows were exposed to equinox photoperiod (12L:12D) for 2 weeks and after that birds were sacrificed (N = 5 per time point) at six time points (ZT1, ZT5, ZT9, ZT13, ZT17 and ZT21; ZT0 is lights on). Daily expression of clock genes was studied using qPCR. Bmal1, Clock, Per2, Per3, Cry1, Cry2 and Npas2 showed daily oscillation in all tissues except Cry2 in hypothalamus, pineal and intestine. We observed tissue-specific expression pattern for all clock and clock-controlled genes. Bmal1 transcripts expressed during early phase of night. Clock acrophase was observed during middle or late day time in the central clock while during early-to-middle phase of night in peripheral tissues. Npas2 expression pattern was similar to Bmal1. Per genes peaked either late at night or early during day time. However, Cry genes were peaked either at late day time (Cry1in retina, liver and intestine; Cry2 in liver and intestine) or at early night phase (Cry1 in hypothalamus, pineal and muscle; Cry2 in hypothalamus, pineal, retina and muscle). Our results are consistent with the autoregulatory circadian feedback loop, and suggest a conserved tissue-level circadian time generation in tree sparrows. Change in peak expression timing of these genes in different tissues implicates tissue-specific contribution of individual clock genes in the circadian time generation.

Energetic costs and implications of the intake of plant secondary metabolites on digestive and renal morphology in two austral passerines.

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.

SUSCEPTIBILITY AND ANTIBODY RESPONSE OF VESPER SPARROWS (POOECETES GRAMINEUS) TO WEST NILE VIRUS: A POTENTIAL AMPLIFICATION HOST IN SAGEBRUSH-GRASSLAND HABITAT.

West Nile virus (WNV) spread to the US western plains states in 2003, when a significant mortality event attributed to WNV occurred in Greater Sage-grouse ( Centrocercus urophasianus ). The role of avian species inhabiting sagebrush in the amplification of WNV in arid and semiarid regions of the North America is unknown. We conducted an experimental WNV challenge study in Vesper Sparrows ( Pooecetes gramineus ), a species common to sagebrush and grassland habitats found throughout much of North America. We found Vesper Sparrows to be moderately susceptible to WNV, developing viremia considered sufficient to transmit WNV to feeding mosquitoes, but the majority of birds were capable of surviving infection and developing a humoral immune response to the WNV nonstructural 1 and envelope proteins. Despite clearance of viremia, after 6 mo, WNV was detected molecularly in three birds and cultured from one bird. Surviving Vesper Sparrows were resistant to reinfection 6 mo after the initial challenge. Vesper sparrows could play a role in the amplification of WNV in sagebrush habitat and other areas of their range, but rapid clearance of WNV may limit their importance as competent amplification hosts of WNV.

Evaluating the stress response as a bioindicator of sub-lethal effects of crude oil exposure in wild house sparrows (Passer domesticus).

Petroleum can disrupt endocrine function in humans and wildlife, and interacts in particularly complex ways with the hypothalamus-pituitary-adrenal (HPA) axis, responsible for the release of the stress hormones corticosterone and cortisol (hereafter CORT). Ingested petroleum can act in an additive fashion with other stressors to cause increased mortality, but it is not clear exactly why--does petroleum disrupt feedback mechanisms, stress hormone production, or both? This laboratory study aimed to quantify the effects of ingested Gulf of Mexico crude oil on the physiological stress response of house sparrows (Passer domesticus). We examined baseline and stress-induced CORT, negative feedback, and adrenal sensitivity in house sparrows given a 1% oil or control diet (n = 12 in each group). We found that four weeks on a 1% oil diet did not alter baseline CORT titers or efficacy of negative feedback, but significantly reduced sparrows' ability to secrete CORT in response to a standardized stressor and adrenocorticotropin hormone injection, suggesting that oil damages the steroid-synthesizing cells of the adrenal. In another group of animals on the same 1% oil (n = 9) or control diets (n = 8), we examined concentrations of eight different blood chemistry parameters, and CORT in feathers grown before and during the feeding experiments as other potential biomarkers of oil exposure. None of the blood chemistry parameters differed between birds on the oil and control diets after two or four weeks of feeding, nor did feather CORT differ between the two groups. Overall, this study suggests that the response of CORT to stressors, but not baseline HPA function, may be a particularly sensitive bioindicator of sub-lethal chronic effects of crude oil exposure.

SPARROW Models Used to Understand Nutrient Sources in the Mississippi/Atchafalaya River Basin.

Nitrogen (N) and phosphorus (P) loading from the Mississippi/Atchafalaya River Basin (MARB) has been linked to hypoxia in the Gulf of Mexico. To describe where and from what sources those loads originate, SPAtially Referenced Regression On Watershed attributes (SPARROW) models were constructed for the MARB using geospatial datasets for 2002, including inputs from wastewater treatment plants (WWTPs), and calibration sites throughout the MARB. Previous studies found that highest N and P yields were from the north-central part of the MARB (Corn Belt). Based on the MARB SPARROW models, highest N yields were still from the Corn Belt but centered over Iowa and Indiana, and highest P yields were widely distributed throughout the center of the MARB. Similar to that found in other studies, agricultural inputs were found to be the largest N and P sources throughout most of the MARB: farm fertilizers were the largest N source, whereas farm fertilizers, manure, and urban inputs were dominant P sources. The MARB models enable individual N and P sources to be defined at scales ranging from SPARROW catchments (∼50 km) to the entire area of the MARB. Inputs of P from WWTPs and urban areas were more important than found in most other studies. Information from this study will help to reduce nutrient loading from the MARB by providing managers with a description of where each of the sources of N and P are most important, thus providing a basis for prioritizing management actions and ultimately reducing the extent of Gulf hypoxia.