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Andrea K. Townsend - One of the best experts on this subject based on the ideXlab platform.
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Apparent inbreeding preference despite inbreeding depression in the American Crow.
Molecular Ecology, 2019Co-Authors: Andrea K. Townsend, Melissa Jones, Katherine H. Getman, Mitch G. Hinton, Conor C. Taff, Sarah S. Wheeler, Ryane M. LogsdonAbstract:: Although matings between relatives can have negative effects on offspring fitness, apparent inbreeding preference has been reported in a growing number of systems, including those with documented inbreeding depression. Here, we examined evidence for inbreeding depression and inbreeding preference in two populations (Clinton, New York, and Davis, California, USA) of the cooperatively breeding American Crow (Corvus brachyrhynchos). We then compared observed inbreeding strategies with theoretical expectations for optimal, adaptive levels of inbreeding, given the inclusive fitness benefits and population-specific magnitude of inbreeding depression. We found that low heterozygosity at a panel of 33 microsatellite markers was associated with low survival probability (fledging success) and low white blood cell counts among offspring in both populations. Despite these costs, our data were more consistent with inbreeding preference than avoidance: The observed heterozygosity among 396 sampled Crow offspring was significantly lower than expected if local adults were mating by random chance. This pattern was consistent across a range of spatial scales in both populations. Adaptive levels of inbreeding, given the magnitude of inbreeding depression, were predicted to be very low in the California population, whereas complete disassortative mating was predicted in the New York population. Sexual conflict might have contributed to the apparent absence of inbreeding avoidance in Crows. These data add to an increasing number of examples of an "inbreeding paradox," where inbreeding appears to be preferred despite inbreeding depression.
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where do winter Crows go characterizing partial migration of American Crows with satellite telemetry stable isotopes and molecular markers
The Auk, 2018Co-Authors: Andrea K. Townsend, Blaire Frett, Anne Mcgarvey, Conor C. TaffAbstract:ABSTRACT Partial migration—a strategy in which some individuals are resident and others are migratory within the same population—is widespread among avian species and could play an important transitional role in the evolution of migratory behavior. Nevertheless, detailed movement data are unavailable for most partial migrant species. We examined migration strategies of the American Crow (Corvus brachyrhynchos), a partially migratory species that overwinters in large communal roosts, from which some birds migrate north to breed. We used a combination of satellite telemetry, isotopic signatures (δ2H), and molecular markers (33 microsatellites) to describe and characterize the migratory movements of individuals from overwintering roosts on the east coast (Utica, New York) and west coast (Davis, California) of the United States. We collected 11,951 data points from 18 satellite-tagged individuals between 2014 and 2018, among which 14 (77.8%) were migratory (8 of 11 and 6 of 7 birds on the west and east coasts...
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west nile virus activity in a winter roost of American Crows corvus brachyrhynchos is bird to bird transmission important in persistence and amplification
Journal of Medical Entomology, 2015Co-Authors: Mitchell G Hinton, Andrea K. Townsend, William K. Reisen, Sarah S. WheelerAbstract:Since its emergence in North America, West Nile virus (WNV) has had a large impact on equines, humans, and wild bird communities, yet gaps remain in our understanding of how the virus persists at temperate latitudes when winter temperatures preclude virus replication and host-seeking activity by mosquito vectors. Bird-to-bird transmission at large communal American Crow roosts could provide one mechanism for WNV persistence. Herein, we describe seasonal patterns of Crow and Culex mosquito abundance, WNV infection rates, and the prevalence of WNV-positive fecal samples at a winter Crow roost to test the hypothesis that bird-to-bird transmission allows WNV to persist at winter Crow roosts. Samples were collected from large winter Crow roosts in the Sacramento Valley of California from January 2013 until August 2014, encompassing two overwintering roost periods. West Nile virus RNA was detected in local Crow carcasses in both summer [13/18 (72% WNV positive)] and winter [18/44 (41% WNV positive)] 2013–2014. Winter infections were unlikely to have arisen by recent bites from infected mosquitoes because Culex host-seeking activity was very low in winter and all Culex mosquitoes collected during winter months tested negative for WNV. Opportunities existed for fecal-oral transfer at the overwintering roost: most carcasses that tested positive for WNV had detectable viral RNA in both kidney and cloacal swabs, suggesting that infected Crows were shedding virus in their feces, and >50% of Crows at the roost were stained with feces by mid-winter. Moreover, 2.3% of fecal samples collected in late summer, when mosquitoes were active, tested positive for WNV RNA. Nevertheless, none of the 1,119 feces collected from three roosts over two winters contained detectable WNV RNA. This study provided evidence of WNV infection in overwintering American Crows without mosquito vector activity, but did not elucidate a mechanism of WNV transmission during winter.
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plastic and the nest entanglement of urban and agricultural Crows
PLOS ONE, 2014Co-Authors: Andrea K. Townsend, Christopher M BarkerAbstract:Much attention has been paid to the impacts of plastics and other debris on marine organisms, but the effects of plastic on terrestrial organisms have been largely ignored. Detrimental effects of terrestrial plastic could be most pronounced in intensively human-modified landscapes (e.g., urban and agricultural areas), which are a source of much anthropogenic debris. Here, we examine the occurrence, types, landscape associations, and consequences of anthropogenic nest material in the American Crow (Corvus brachyrhynchos), a North American species that breeds in both urban and agricultural landscapes. We monitored 195 nestlings in 106 nests across an urban and agricultural gradient in the Sacramento Valley, California, USA. We found that 85.2% of Crow nests contained anthropogenic material, and 11 of 195 nestlings (5.6%) were entangled in their nests. The length of the material was greater in nests in agricultural territories than in urban territories, and the odds of entanglement increased 7.55 times for each meter of anthropogenic material in the nest. Fledging success was significantly lower for entangled than for unentangled nestlings. In all environments, particularly urban, agricultural, and marine, careful disposal of potential hazards (string, packing and hay bale twine, balloon ribbon, wire, fishing line) could reduce the occurrence of entanglement of nestling birds.
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non west nile virus associated mortality in a population of American Crows corvus brachyrhynchos a gross and histopathologic study
Journal of Veterinary Diagnostic Investigation, 2010Co-Authors: Andrew D Miller, Andrea K. Townsend, Anne B Clark, Kevin J Mcgowan, Amy L Glaser, Lisa A Patrican, Elizabeth Dobson, Elizabeth L BucklesAbstract:The American Crow (Corvus brachyrhynchos) is a common urban and rural inhabitant of the Northeast and Midwest United States that is commonly infected with West Nile virus (WNV). The current study was initiated to determine non-WNV-associated causes of mortality in the American Crow. All animals (40/40) tested negative for WNV infection via polymerase chain reaction and had no evidence of infection based on immunohistochemistry. Common gross necropsy findings included external trauma (6/40), hepatosplenomegaly (6/40), poxviral dermatitis (5/40), and pneumonia (3/40). Common histologic findings included endoparasitism (32/40), multifocal hepatic and splenic necrosis (7/40), pigment accumulation in the spleen (5/40), and disseminated bacterial infection (3/40). The most significant and debilitating diseases included fungal pneumonia and poxvirus-associated lesions. The present report increases the knowledge of diseases present in the American Crow population.
John Klicka - One of the best experts on this subject based on the ideXlab platform.
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cryptic and extensive hybridization between ancient lineages of American Crows
Molecular Ecology, 2020Co-Authors: David L Slager, Kevin L Epperly, Sievert Rohwer, Chris Wood, Caroline R Van Hemert, John KlickaAbstract:Most species and therefore most hybrid zones have historically been defined using phenotypic characters. However, both speciation and hybridization can occur with negligible morphological differentiation. Recently developed genomic tools provide the means to better understand cryptic speciation and hybridization. The Northwestern Crow (Corvus caurinus) and American Crow (Corvus brachyrhynchos) are continuously distributed sister taxa that lack reliable traditional characters for identification. In this first population genomic study of Northwestern and American Crows, we use genomic SNPs (nuDNA) and mtDNA to investigate the degree of genetic differentiation between these Crows and the extent to which they may hybridize. Our results indicate that American and Northwestern Crows have distinct evolutionary histories, supported by two nuDNA ancestry clusters and two 1.1%-divergent mtDNA clades dating to the late Pleistocene, when glacial advances may have isolated Crow populations in separate refugia. We document extensive hybridization, with geographic overlap of mtDNA clades and admixture of nuDNA across >900 km of western Washington and western British Columbia. This broad hybrid zone consists of late-generation hybrids and backcrosses, but not recent (e.g., F1) hybrids. Nuclear DNA and mtDNA clines had concordant widths and were both centred in southwestern British Columbia, farther north than previously postulated. Overall, our results suggest a history of reticulate evolution in American and Northwestern Crows, perhaps due to recurring neutral expansion(s) from Pleistocene glacial refugia followed by lineage fusion(s). However, we do not rule out a contributing role for more recent potential drivers of hybridization, such as expansion into human-modified habitats.
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cryptic and extensive hybridization between ancient lineages of American Crows
bioRxiv, 2018Co-Authors: David L Slager, Kevin L Epperly, Sievert Rohwer, Chris Wood, Caroline R Van Hemert, John KlickaAbstract:Abstract Most species and therefore most hybrid zones have historically been described using phenotypic characters. However, both speciation and hybridization can occur with negligible morphological differentiation. The Northwestern Crow (Corvus caurinus) and American Crow (Corvus brachyrhynchos) are sister taxonomic species with a continuous distribution that lack reliable traditional characters for identification. In this first population genomic study of Northwestern and American Crows, we use genomic SNPs (nuDNA) and mtDNA to investigate whether these Crows are genetically differentiated and the extent to which they may hybridize. We found that American and Northwestern Crows have distinct evolutionary histories, supported by two nuDNA ancestry clusters and two 1.1%-divergent mtDNA clades dating to the late Pleistocene, when glacial advances may have isolated Crow populations in separate refugia. We document extensive hybridization, with geographic overlap of mtDNA clades and admixture of nuDNA across >1,400 km of western Washington and western British Columbia. This broad hybrid zone consists of late-generation hybrids and backcrosses, not recent (e.g., F1) hybrids. Nuclear DNA and mtDNA clines were both centered in southwestern British Columbia, farther north than previously postulated. The mtDNA cline was narrower than the nuDNA cline, consistent with Haldane’s rule but not sex-biased dispersal. Overall, our results suggest a history of reticulate evolution in American and Northwestern Crows, consistent with potentially recurring neutral expansion(s) from Pleistocene glacial refugia followed by lineage fusion(s). However, we do not rule out a contributing role for more recent potential drivers of hybridization, such as expansion into human-modified habitats.
Laura D Kramer - One of the best experts on this subject based on the ideXlab platform.
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multiplexed microsatellite loci in American Crow corvus brachyrhynchos a severely affected natural host of west nile virus
Infection Genetics and Evolution, 2012Co-Authors: Claudio Verdugo, A M Clark, Dhani Prakoso, Laura D Kramer, Maureen T LongAbstract:Recent advances in high throughput molecular techniques have allowed the development of cost- and time-effective libraries of molecular markers, such as microsatellites, for population genetic studies in non-model species. The American Crow, Corvus brachyrhynchos, is recognized to be one of the species that has been most negatively affected by the emergence of West Nile virus (WNV) in North America in 1999. Genetic monitoring of the process of a declining population after the introduction of an infectious disease can provide insights into the demographic and evolutionary impact of a pathogen in a natural host population over time. In this study, shotgun pyrosequencing and validation of previously published cross-species markers were the approaches used to identify and develop a set of 32 polymorphic loci for the C. brachyrhynchos. Since the American Crow is morphologically similar to the sympatric species Fish Crow (Corvus ossifragus), we also designed a real-time PCR protocol to rapidly differentiate these two species using a set of primers and probes that can discriminate a section of the COI gene at the mitochondrial DNA. These new markers together with a faster method for species verification will allow further detailed studies to characterize and compare genetic diversity of historic and contemporary C. brachyrhynchos populations.
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characterization of a small plaque variant of west nile virus isolated in new york in 2000
Virology, 2007Co-Authors: Yongqing Jia, Laura D Kramer, Robin M Moudy, Alan P Dupuis, Kiet A Ngo, Joseph G Maffei, Greta V S Jerzak, Mary A Franke, Elizabeth B KauffmanAbstract:A small-plaque variant (SP) of West Nile virus (WNV) was isolated in Vero cell culture from kidney tissue of an American Crow collected in New York in 2000. The in vitro growth of the SP and parental (WT) strains was characterized in mammalian (Vero), avian (DF-1 and PDE), and mosquito (C6/36) cells. The SP variant replicated less efficiently than did the WT in Vero cells. In avian cells, SP growth was severely restricted at high temperatures, suggesting that the variant is temperature sensitive. In mosquito cells, growth of SP and WT was similar, but in vivo in Culex pipiens (L.) there were substantial differences. Relative to WT, SP exhibited reduced replication following intrathoracic inoculation and lower infection, dissemination, and transmission rates following oral infection. Analysis of the full length sequence of the SP variant identified sequence differences which led to only two amino acid substitutions relative to WT, prM P54S and NS2A V61A.
Kevin J Mcgowan - One of the best experts on this subject based on the ideXlab platform.
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acoustic profiling in a complexly social species the American Crow caws encode information on caller sex identity and behavioural context
Bioacoustics-the International Journal of Animal Sound and Its Recording, 2015Co-Authors: Exu Anton Mates, Anne B Clark, Robin R Tarter, Kevin J McgowanAbstract:Previous research on inter-individual variation in the calls of corvids has largely been restricted to single call types, such as alarm or contact calls, and has rarely considered the effects of age on call structure. This study explores structural variation in a contextually diverse set of ‘caw’ calls of the American Crow (Corvus brachyrhynchos), including alarm, foraging recruitment and territorial calls, and searches for structural features that may be associated with behavioural context and caller sex, age and identity. Automated pitch detection algorithms are used to generate 23 pitch-related and spectral parameters for a collection of caws from 18 wild, marked Crows. Using principal component analysis and mixed models, we identify independent axes of acoustic variation associated with behavioural context and with caller sex, respectively. We also have moderate success predicting caller sex and identity from call structure. However, we do not find significant acoustic variation with respect to caller...
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non west nile virus associated mortality in a population of American Crows corvus brachyrhynchos a gross and histopathologic study
Journal of Veterinary Diagnostic Investigation, 2010Co-Authors: Andrew D Miller, Andrea K. Townsend, Anne B Clark, Kevin J Mcgowan, Amy L Glaser, Lisa A Patrican, Elizabeth Dobson, Elizabeth L BucklesAbstract:The American Crow (Corvus brachyrhynchos) is a common urban and rural inhabitant of the Northeast and Midwest United States that is commonly infected with West Nile virus (WNV). The current study was initiated to determine non-WNV-associated causes of mortality in the American Crow. All animals (40/40) tested negative for WNV infection via polymerase chain reaction and had no evidence of infection based on immunohistochemistry. Common gross necropsy findings included external trauma (6/40), hepatosplenomegaly (6/40), poxviral dermatitis (5/40), and pneumonia (3/40). Common histologic findings included endoparasitism (32/40), multifocal hepatic and splenic necrosis (7/40), pigment accumulation in the spleen (5/40), and disseminated bacterial infection (3/40). The most significant and debilitating diseases included fungal pneumonia and poxvirus-associated lesions. The present report increases the knowledge of diseases present in the American Crow population.
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growth and nutritional state of American Crow nestlings vary between urban and rural habitats
Ecological Applications, 2009Co-Authors: Rebecca S Heiss, Anne B Clark, Kevin J McgowanAbstract:In urbanized areas, many adult birds find sufficient foods to survive, but the anthropogenic foods that are abundant there may be detrimental to nestling growth. In fact, American Crow (Corvus brachyrhynchos) nestlings are smaller in suburban than rural areas, possibly because of nutrient limitation. Here, we seek to identify possible causes of size differences by comparing both size and blood chemistry measures in rural and suburban Crow nestlings. We quantified land use in known Crow territories and distinguished three distinct environments: suburban-residential, suburban-managed (e.g., golf courses), and rural. We measured nestlings near fledging age in each environment and bled them for determination of unbound plasma calcium, total protein, and corticosterone. We supplemented a subset of broods in suburban-residential and rural areas with a food high in protein and calcium. Rural nestlings were significantly larger than suburban-residential Crows and had higher total serum protein. Nestlings in suburban-managed areas were intermediate in size and serum protein but had the lowest plasma calcium levels. Nestling corticosterone levels did not differ significantly among habitats, indicating that, although suburban nestlings may be food-limited, they were not starving. Supplemented nestlings in suburban-residential areas were significantly larger in some growth measures than their unsupplemented counterparts. Unexpectedly, supplemented rural nestlings were significantly smaller than unsupplemented rural ones, suggesting that parents use easily accessible food even when it is nutritionally suboptimal. Our results indicate that nestlings in suburban areas are nutrient restricted, rather than calorie restricted.
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reproductive partitioning and the assumptions of reproductive skew models in the cooperatively breeding American Crow
Animal Behaviour, 2009Co-Authors: Andrea K. Townsend, Anne B Clark, Kevin J Mcgowan, Irby J LovetteAbstract:Understanding the benefits of cooperative breeding for group members of different social and demographic classes requires knowledge of their reproductive partitioning and genetic relatedness. During 2004–2007, we examined parentage as a function of relatedness and social interactions among members of 21 American Crow, Corvus brachyrhynchos, family groups. Paired female breeders monopolized maternity of all offspring in their broods, whereas paired male breeders sired 82.7% of offspring, within-group auxiliary males sired 6.9% of offspring and extragroup males sired 10.4% of offspring. Although adult females had fewer opportunities for direct reproduction as auxiliaries than males, they appeared to have earlier opportunities for independent breeding. These different opportunities for direct reproduction probably contributed to the male-biased adult auxiliary sex ratio. Patterns of reproductive partitioning and conflict among males were most consistent with a synthetic reproductive skew model, in which auxiliaries struggled with breeders for a limited reproductive share, beyond which breeders could evict them. Counter to a frequent assumption of reproductive skew models, female breeders appeared to influence paternity, although their interests might have agreed with the interests of their paired males. Unusual among cooperative breeders, close inbreeding and incest occurred in this population. Incest avoidance between potential breeders did not significantly affect reproductive skew.
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the inflected alarm caw of the American Crow differences in acoustic structure among individuals and sexes
The Condor, 2006Co-Authors: Jessica L Yorzinski, Kevin J Mcgowan, Sandra L Vehrencamp, Anne B ClarkAbstract:Abstract Previous research on individual differences in the acoustic structure of vocalizations and vocal recognition has largely focused on the contexts of parent-offspring interactions, territory defense, sexual interactions, and group cohesion. In contrast, few studies have examined individual differences in the acoustic structure of mobbing and alarm calls. The purpose of this study was to explore individual differences in the acoustic structure of the inflected alarm caw of the American Crow (Corvus brachyrhynchos). The alarm caws of 15 wild, marked individuals were recorded and 25 acoustic measurements were made automatically using customized software. A stepwise discriminant function analysis showed that 20 of the 25 variables were important in discriminating among individuals, with 65% classification success. We used factor analysis to reduce the large number of variables to a set of seven meaningful call features. All of these features differed among individuals, suggesting that American Crows ha...
Ryane M. Logsdon - One of the best experts on this subject based on the ideXlab platform.
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Apparent inbreeding preference despite inbreeding depression in the American Crow.
Molecular Ecology, 2019Co-Authors: Andrea K. Townsend, Melissa Jones, Katherine H. Getman, Mitch G. Hinton, Conor C. Taff, Sarah S. Wheeler, Ryane M. LogsdonAbstract:: Although matings between relatives can have negative effects on offspring fitness, apparent inbreeding preference has been reported in a growing number of systems, including those with documented inbreeding depression. Here, we examined evidence for inbreeding depression and inbreeding preference in two populations (Clinton, New York, and Davis, California, USA) of the cooperatively breeding American Crow (Corvus brachyrhynchos). We then compared observed inbreeding strategies with theoretical expectations for optimal, adaptive levels of inbreeding, given the inclusive fitness benefits and population-specific magnitude of inbreeding depression. We found that low heterozygosity at a panel of 33 microsatellite markers was associated with low survival probability (fledging success) and low white blood cell counts among offspring in both populations. Despite these costs, our data were more consistent with inbreeding preference than avoidance: The observed heterozygosity among 396 sampled Crow offspring was significantly lower than expected if local adults were mating by random chance. This pattern was consistent across a range of spatial scales in both populations. Adaptive levels of inbreeding, given the magnitude of inbreeding depression, were predicted to be very low in the California population, whereas complete disassortative mating was predicted in the New York population. Sexual conflict might have contributed to the apparent absence of inbreeding avoidance in Crows. These data add to an increasing number of examples of an "inbreeding paradox," where inbreeding appears to be preferred despite inbreeding depression.