Powdermill Avian Research Center

Rector, PA, United States

Powdermill Avian Research Center

Rector, PA, United States

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Henning J.D.,University of Pittsburgh | DeGroote L.,Powdermill Avian Research Center | Dahlin C.R.,University of Pittsburgh
Journal of Virological Methods | Year: 2015

In 1999, West Nile virus (WNV) first appeared in the United States and has subsequently infected more than a million people and untold numbers of wildlife. Though primarily an avian virus, WNV can also infect humans and horses. The current status of WNV and its effects on wildlife in Pennsylvania (PA) is sparsely monitored through sporadic testing of dead birds. In order to acquire a more comprehensive understanding of the status of WNV in wild birds, a study was designed and implemented to sample populations of migratory and local birds at Powdermill Nature Reserve near Rector, PA. Resident and migratory bird species totaling 276 individuals were sampled cloacally and orally to compare the effectiveness of sampling methods. The presence of WNV was tested for using RT-PCR. Two positive samples were found, one from a migrating Tennessee warbler and another from an American robin. The low infection rates indicate that WNV may not be a critical conservation concern in the Westmoreland County region of PA. There was also agreement between oral and cloacal swabs, which provides support for both methods. This study describes a surveillance method that is easily incorporated into any banding operation and which determines the risks of WNV to various bird populations. © 2015 Elsevier B.V.


Van Buskirk J.,University of Zürich | Mulvihill R.S.,Powdermill Avian Research Center | Leberman R.C.,Powdermill Avian Research Center
Ecology and Evolution | Year: 2012

Recent climate change has been linked to shifts in the timing of life-cycle events in many organisms, but there is debate over the degree to which phenological changes are caused by evolved genetic responses of populations or by phenotypic plasticity of individuals. We estimated plasticity of spring arrival date in 27 species of bird that breed in the vicinity of an observatory in eastern North America. For 2441 individuals detected in multiple years, arrival occurred earlier during warm years, especially in species that migrate short distances. Phenotypic plasticity averaged -0.93 days oC -1 ± 0.70 (95% CI). However, plasticity accounted for only 13-25% of the climate-induced trend in phenology observed over 46 years. Although our approach probably underestimates the full scope of plasticity, the data suggest that part of the response to environmental change has been caused by microevolution. The estimated evolutionary rates are plausible (0.016 haldanes). © 2012 The Authors. Ecology and Evolution published by Blackwell Publishing Ltd.


Griffiths E.T.,Cornell University | Keen S.C.,Cornell University | Lanzone M.,Powdermill Avian Research Center | Farnsworth A.,Cornell University
PLoS ONE | Year: 2016

Bird species often use flight calls to engage in social behavior, for instance maintain group cohesion and to signal individual identity, kin or social associations, or breeding status of the caller. Additional uses also exist, in particular among migrating songbirds for communication during nocturnal migration. However, our understanding of the information that these vocalizations convey is incomplete, especially in nocturnal scenarios. To examine whether information about signaler traits could be encoded in flight calls we quantified several acoustic characteristics from calls of a nocturnally migrating songbird, the American Redstart. We recorded calls from temporarily captured wild specimens during mist-netting at the Powdermill Avian Research Center in Rector, PA. We measured call similarity among and within individuals, genders, and age groups. Calls from the same individual were significantly more similar to one another than to the calls of other individuals, and calls were significantly more similar among individuals of the same sex than between sexes. Flight calls from hatching-year and after hatching-year individuals were not significantly different. Our results suggest that American Redstart flight calls may carry identifiers of gender and individual identity. To our knowledge, this is the first evidence of individuality or sexual dimorphism in the flight calls of a migratory songbird. Furthermore, our results suggest that flight calls may have more explicit functions beyond simple group contact and cohesion. Nocturnal migration may require coordination among numerous individuals, and the use of flight calls to transmit information among intra- and conspecifics could be advantageous. Applying approaches that account for such individual and gender information may enable more advanced research using acoustic monitoring. © 2016 Griffiths et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.


Vitz A.C.,Ohio State University | Vitz A.C.,Powdermill Avian Research Center | Rodewald A.D.,Ohio State University
Auk | Year: 2010

Although postfledging movement patterns have been described for several species, the factors that influence these movements remain unclear. We quantified natal home-range size and dispersal patterns of two songbird species and evaluated the relative importance of nestling condition, brood size, predation risk, and habitat structure on postfledging movements. We radiotagged and tracked 51 Ovenbirds (Seiurus aurocapilla) and 60 Worm-eating Warblers (Helmitheros vermivorum) between 2004 and 2007. For each radiotagged bird, we calculated distances from daily locations to the original nest, successive distances between daily locations, mean dispersal distance from the natal area, number of days before dispersal, and natal home-range size. We built and ranked alternative models to represent mechanisms that potentially influence movements 2 days after fledging. The natal home-range size of Worm-eating Warblers (10.4 ha ± 1.50 [SE]) was twice that of Ovenbirds (5.0 ha ± 0.56). Fledgling age was positively correlated with the distance moved from the nest and between daily locations. Relative body mass at the time of fledging was positively associated with the mean distance between daily locations 2 days after fledging. This research generated two important insights into postfledging ecology: (1) that conditions experienced by birds in the nest may ultimately facilitate or constrain their ability to locate suitable habitat, which is known to influence fledgling survival; and (2) that large natal home ranges and relatively long dispersal distances away from the natal area may contribute to area sensitivity in songbirds. © 2010 by The American Ornithologists' Union. All rights reserved.


Vitz A.C.,Ohio State University | Vitz A.C.,Powdermill Avian Research Center | Rodewald A.D.,Ohio State University
Journal of Field Ornithology | Year: 2012

Use of early successional habitat by mature forest birds during the postfledging period is well documented, but reasons for this habitat shift remain elusive. Although forest-breeding songbirds are primarily insectivorous during the nestling and early fledgling periods due to high protein requirements, older fledglings may adopt a heavily frugivorous diet. Our objectives were to use stable isotopes to examine the dietary trophic level of juveniles of three species of mature forest songbirds to determine if juvenile songbirds heavily consume fruit resources during the postfledging period and to evaluate a possible link between diet and energetic condition. We collected the outer right rectrix and several body feathers from 34 Wood Thrushes (Hylocichla mustelina), 34 Ovenbirds (Seiurus aurocapilla), and 35 Scarlet Tanagers (Piranga olivacea) captured in regenerating clearcuts in southeastern Ohio in 2005 and 2006. We also collected fruit and arthropod samples from each clearcut. Isotopic values of body feathers were significantly higher (more enriched) than those of rectrices in all cases except values of δ 13C for Ovenbirds where we found no difference between body and rectrix feathers. These results suggest that juvenile songbirds did not undergo a strong shift to frugivory during the postfledging period, and arthropods were the primary source of protein during the period when rectrix and body feathers were growing. In addition, the energetic condition of birds was not related to the isotopic signature of feathers. Although our results are inconsistent with the hypothesis that juveniles move into regenerating clearcuts enabling them to shift to a primarily frugivorous diet during the postfledging period, they may consume fruit for nonprotein requirements, such as lipids and carbohydrates. © 2012 The Authors. Journal of Field Ornithology © 2012 Association of Field Ornithologists.


Bakermans M.H.,Ohio State University | Bakermans M.H.,Indiana University of Pennsylvania | Rodewald A.D.,Ohio State University | Vitz A.C.,Ohio State University | Vitz A.C.,Powdermill Avian Research Center
Journal of Wildlife Management | Year: 2012

Managing for forest wildlife requires attention not only to quantity but quality of forests within the landscape. We examined the extent to which local structural attributes and landscape context of forest stands explained variation in density and reproductive success of mature forest birds across 12 sites in southeast Ohio, USA, 2004-2006. Results suggest that several structural characteristics influenced bird-habitat relationships in our study. Densities of 3 songbird species (i.e., ovenbird [Seiurus aurocapilla], cerulean warbler [Setophaga cerulea], and scarlet tanager [Piranga olivacea]) were positively related to canopy openness, which is usually a function of canopy gaps. Habitat attributes described by ground litter, understory density, and canopy height were positively associated with densities of ground (i.e., worm-eating warbler [Helmitheros vermivorum]), or shrub nesting species (i.e., Kentucky and hooded warblers [Geothlypis formosa and Setophaga citrina], respectively). Furthermore, the number of small trees likely drove the positive relationship between density of wood thrush (Hylocichla mustelina), a subcanopy nester. After accounting for temporal variability in daily nest survival rates, the odds of nest survival for all species increased 10.5% for every 1% increase in canopy openness and decreased 1.4% for each 5% increase in understory vegetation density. Habitat-nest survival relationships were not apparent at the level of the individual species. Our results suggest that structural attributes produced by increasing habitat heterogeneity may be necessary for conservation of forest bird communities. © 2012 The Wildlife Society.


Van Buskirk J.,University of Zürich | Van Buskirk J.,University of Melbourne | Mulvihill R.S.,Powdermill Avian Research Center | Leberman R.C.,Powdermill Avian Research Center
Oikos | Year: 2010

Recent climate change has caused comparatively rapid shifts in the phenology and geographic distributions of many plants and animals. However, there is debate over the degree to which populations can meet the challenges of climate change with evolutionary or phenotypic responses in life history and morphology. We report that migrating birds captured at a banding station in western Pennsylvania, USA, have exhibited steadily decreasing fat-free mass and wing chord since 1961, consistent with a response to a warmer climate. This confirms that phenotypic responses to climate change are currently underway in entire avian assemblages. Declines in body size were not explained by an index of habitat condition within the breeding or wintering distributions. Instead, size was negatively correlated with temperature in the previous year, and long-term trends were associated with the direction of natural selection acting on size over the winter: species undergoing the strongest selection favoring small wing chord showed the most rapid long-term declines in wing. Phenotypic changes are therefore in line with the prevailing selection regime. © 2009 The Authors.


Keen S.,Bioacoustics Research Program | Ross J.C.,Cornell Laboratory of Ornithology | Griffiths E.T.,Bioacoustics Research Program | Lanzone M.,Powdermill Avian Research Center | Farnsworth A.,Cornell Laboratory of Ornithology
Ecological Informatics | Year: 2014

Numerous methods are available for analysis of avian vocalizations, but few research efforts have compared recent methods for calculating and evaluating similarity among calls, particularly those collected in the field. This manuscript compares a suite of methodologies for analyzing flight calls of New World warblers, investigating the effectiveness of four techniques for calculating call similarity: (1) spectrographic cross-correlation, (2) dynamic time warping, (3) Euclidean distance between spectrogram-based feature measurements, and (4) random forest distance between spectrogram-based feature measurements. We tested these methods on flight calls, which are short, structurally simple vocalizations typically used during nocturnal migration, as these signals may contain important ecological or demographic information. Using the four techniques listed above, we classified flight calls from three datasets, one collected from captive birds and two collected from wild birds in the field. Each dataset contained an equal number of calls from four warbler species commonly recorded during acoustic monitoring: American Redstart, Chestnut-sided Warbler, Hooded Warbler, and Ovenbird. Using captive recordings to train the classification models, we created four similarity-based classifiers which were then tested on the captive and field datasets. We show that these classification methods are limited in their ability to successfully classify the calls of these warbler species, and that classification accuracy was lower on field recordings than captive recordings for each of the tested methods. Of the four methods we compared, the random forest technique had the highest classification accuracy, enabling correct classification of 67.6% of field recordings. To compare the performance of the automated techniques to manual classification, the most common method used in flight call research, human experts were also asked to classify calls from each dataset. The experts correctly classified approximately 90% of field recordings, indicating that although the automated techniques are faster, they remain less accurate than manual classification. However, because of the challenges inherent to these data, such as the structural similarity among the flight calls of focal species and the presence of environmental noise in the field recordings, some of the tested automated classification techniques may be acceptable for real-world applications. We believe that this comparison of broadly applicable methodologies provides information that will prove to be useful for analysis, detection and classification of short duration signals. Based on our results, we recommend that a combination of feature measurements and random forest classification can be used to assign flight calls to species, while human experts oversee the process. © 2014 Elsevier B.V.


Vitz A.C.,Ohio State University | Vitz A.C.,Powdermill Avian Research Center | Rodewald A.D.,Ohio State University
Condor | Year: 2011

Habitat quality of a bird's breeding grounds has been typically evaluated by investigating patterns in nesting success, whereas events that follow fledging have been largely ignored. One especially overlooked aspect of breeding-habitat quality is how habitat affects the survival of young birds after they leave the nest, a period when mortality is notoriously high. We studied survival of fledglings of two mature-forest species, the Ovenbird (Seiurus aurocapilla) and Worm-eating Warbler (Helmitheros vermivorum), to identify intrinsic (e.g., age, condition) and extrinsic (e.g., habitat structure) factors that influence survival. From 2004 to 2007, we radio-tagged 51 Ovenbird and 60 Worm-eating Warbler fledglings in southeast Ohio. We recorded the birds' locations daily and compared vegetation structure at the fledglings' and paired random locations. Using known-fate models in program MARK, we calculated post-fledging survival to be 65% for the Ovenbirds (51 days after fledging) and 67% for the Worm-eating Warblers (31 days after fledging). Fledglings' condition at the time of radio tagging was positively related to survival after fledging, implying carryover effects from the nestling period. Fledglings of both species used dense vegetation with 40-60% more woody stems in the understory than at random locations. Moreover, use of dense vegetation actually promoted survival. Although riparian thickets and tree-fall gaps within some forests may provide abundant habitat for fledglings, other forests may lack the structural attributes that promote fledglings' survival. Our findings highlight the importance of both breeding and post-fledging requirements being considered in avian conservation plans. © The Cooper Ornithological Society 2011.


PubMed | Cornell University and Powdermill Avian Research Center
Type: Journal Article | Journal: PloS one | Year: 2016

Bird species often use flight calls to engage in social behavior, for instance maintain group cohesion and to signal individual identity, kin or social associations, or breeding status of the caller. Additional uses also exist, in particular among migrating songbirds for communication during nocturnal migration. However, our understanding of the information that these vocalizations convey is incomplete, especially in nocturnal scenarios. To examine whether information about signaler traits could be encoded in flight calls we quantified several acoustic characteristics from calls of a nocturnally migrating songbird, the American Redstart. We recorded calls from temporarily captured wild specimens during mist-netting at the Powdermill Avian Research Center in Rector, PA. We measured call similarity among and within individuals, genders, and age groups. Calls from the same individual were significantly more similar to one another than to the calls of other individuals, and calls were significantly more similar among individuals of the same sex than between sexes. Flight calls from hatching-year and after hatching-year individuals were not significantly different. Our results suggest that American Redstart flight calls may carry identifiers of gender and individual identity. To our knowledge, this is the first evidence of individuality or sexual dimorphism in the flight calls of a migratory songbird. Furthermore, our results suggest that flight calls may have more explicit functions beyond simple group contact and cohesion. Nocturnal migration may require coordination among numerous individuals, and the use of flight calls to transmit information among intra- and conspecifics could be advantageous. Applying approaches that account for such individual and gender information may enable more advanced research using acoustic monitoring.

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