Wiley J.W.,Western Foundation of Vertebrate Zoology
Journal of Raptor Research | Year: 2010
The Ashy-faced Owl (Tyto glaucops) is endemic to Hispaniola, where the Barn Owl (T. alba) became established after ca. 1950. I examined 8322 vertebrate prey of the two species, using regurgitated pellets and prey remains from 12 localities in five habitats in the Dominican Republic to determine diets and feeding-niche characteristics of the owls. Owl diets differed among prey classes in frequency and biomass. Mammals, mainly introduced rodents, predominated in the diets of Ashy-faced Owls (52.0% frequency, 73.9% biomass) and Barn Owls (76.7% frequency, 90.7% biomass), with bats forming a substantial proportion for both species (Ashy-faced Owl: 11.1% frequency, 2.6% mass; Barn Owl: 12.2% frequency, 2.2% mass). Birds made up a greater proportion of Ashy-faced Owl prey (28.8% frequency, 14.8% mass) than of Barn Owl prey (12.3% frequency, 5.1% mass). Reptiles and amphibians were unequally represented in Ashy-faced (19.2% frequency, 11.3% mass) and Barn (11.1% frequency, 4.3% mass) owl diets. Niche overlap was moderate overall (α = 0.60). Ashy-faced Owl prey materials contained 125 vertebrate species, whereas Barn Owl materials included 114 species, with 92 species in common between the two owls. The Ashy-faced Owl had a more diverse prey base (H9 = 3.04, D = 6.32, J = 0.610) than did the Barn Owl (H9 = 2.21, D = 2.93, J = 0.444). I could not determine whether niche overlap resulted in competition between the two owl species. © 2010 The Raptor Research Foundation, Inc.
Doyle J.M.,Purdue University |
Katzner T.E.,West Virginia University |
Katzner T.E.,U.S. Department of Agriculture |
Bloom P.H.,Western Foundation of Vertebrate Zoology |
And 3 more authors.
PLoS ONE | Year: 2014
Biologists routinely use molecular markers to identify conservation units, to quantify genetic connectivity, to estimate population sizes, and to identify targets of selection. Many imperiled eagle populations require such efforts and would benefit from enhanced genomic resources. We sequenced, assembled, and annotated the first eagle genome using DNA from a male golden eagle (Aquila chrysaetos) captured in western North America. We constructed genomic libraries that were sequenced using Illumina technology and assembled the high-quality data to a depth of ∼40x coverage. The genome assembly includes 2,552 scaffolds >10 Kb and 415 scaffolds >1.2 Mb. We annotated 16,571 genes that are involved in myriad biological processes, including such disparate traits as beak formation and color vision. We also identified repetitive regions spanning 92 Mb (∼6% of the assembly), including LINES, SINES, LTR-RTs and DNA transposons. The mitochondrial genome encompasses 17,332 bp and is ∼91% identical to the Mountain Hawk-Eagle (Nisaetus nipalensis). Finally, the data reveal that several anonymous microsatellites commonly used for population studies are embedded within protein-coding genes and thus may not have evolved in a neutral fashion. Because the genome sequence includes ∼800,000 novel polymorphisms, markers can now be chosen based on their proximity to functional genes involved in migration, carnivory, and other biological processes. © 2014 Doyle et al.
Stanley T.R.,U.S. Geological Survey |
Teel S.,National Park Service |
Hall L.S.,Western Foundation of Vertebrate Zoology |
Dye L.C.,National Park Service |
Laughrin L.L.,University of California at Santa Barbara
Wildlife Society Bulletin | Year: 2012
Island loggerhead shrikes (Lanius ludovicianus anthonyi) are an endemic, genetically distinct subspecies of loggerhead shrike on California's Santa Rosa, Santa Cruz, and Santa Catalina Islands (USA). This subspecies is listed as a Species of Special Concern by the California Department of Fish and Game and has been petitioned for federal listing under the Endangered Species Act. The combination of suspected low numbers and the possibility of federal listing, prompted us to undertake a study to rigorously estimate the number of remaining individuals on Santa Rosa and Santa Cruz Islands. During the 2009 and 2010 breeding seasons, we surveyed sample units on Santa Rosa and Santa Cruz Islands using a double-observer method with independent observers to estimate joint detection probabilities (p), where we selected units under a stratified random sampling design. We estimated shrike abundance to be 169 in 2009 (p = 0.476) and 240 in 2010 (p = 0.825) for Santa Rosa Island, and 35 in 2009 (p = 0.816) and 42 in 2010 (p = 0.710) for Santa Cruz Island. These numbers, especially for Santa Rosa Island, are higher than previously reported but nevertheless are still low. Rapid vegetation change on both islands due to recent removal of nonnative herbivores may threaten the habitat and status of this subspecies and, therefore, we suggest that intensive demographic and habitat use research be initiated immediately to obtain additional information vital for the management of this subspecies. © 2011 The Wildlife Society.
Pike J.E.,18744 Beach Blvd. |
Garrett K.L.,Natural History Museum of Los Angeles County |
Searcy A.J.,Western Foundation of Vertebrate Zoology
Western Birds | Year: 2014
The California Bird Records Committee reached decisions on 280 records involving 525 individuals of 88 species and two species pairs documented since the 37th report (Nelson et al. 2013), endorsing 226 records of 471 individuals. The recent addition of the Scaly-breasted Munia (formerly Nutmeg Mannikin, Lonchura punctulata) to the state list, and the split of the Sage Sparrow into the Sagebrush Sparrow (Artemisiospiza nevadensis) and Bell's Sparrow (A. belli), combined with first accepted state records of the Northern Gannet (Morus bassanus), Gray Hawk (Buteo plagiatus), and Common Cuckoo (Cuculus canorus) outlined in this report, brings California's total list of accepted species to 654, 11 of which, including the munia, are established introductions. Other notable records detailed in this report are of the Common Crane (Grus grus), Wood Sandpiper (Tringa glareola), and Varied Bunting (Passerina versicolor).
Poessel S.A.,U.S. Geological Survey |
Bloom P.H.,Western Foundation of Vertebrate Zoology |
Braham M.A.,West Virginia University |
Katzner T.E.,U.S. Geological Survey
European Journal of Wildlife Research | Year: 2016
Animal movements can determine the population dynamics of wildlife. We used telemetry data to provide insight into the causes and consequences of local and long-distance movements of multiple age classes of conservation-reliant golden eagles (Aquila chrysaetos) in the foothills and mountains near Tehachapi, California. We estimated size and habitat-related correlates of 324 monthly 95 % home ranges and 317 monthly 50 % core areas for 25 birds moving locally over 2.5 years. We also calculated daily, hourly, and total distances traveled for the five of these birds that engaged in long-distance movements. Mean (±SD) monthly home-range size was 253.6 ± 429.4 km2 and core-area size was 26.4 ± 49.7 km2. Consistent with expectations, space used by pre-adults increased with age and was season-dependent but, unexpectedly, was not sex-dependent. For all ages and sexes, home ranges and core areas were dominated by both forest & woodland and shrubland & grassland habitat types. When moving long distances, eagles traveled up to 1588.4 km (1-way) in a season at highly variable speeds (63.7 ± 69.0 km/day and 5.2 ± 10.4 km/h) that were dependent on time of day. Patterns of long-distance movements by eagles were determined by age, yet these movements had characteristics of more than one previously described movement category (migration, dispersal, etc.). Our results provide a context for differentiating among types of movement behaviors and their population-level consequences and, thus, have implications for management and conservation of golden eagle populations. © 2016 Springer-Verlag Berlin Heidelberg (outside the USA)