Here, we test the hypothesis that American Crows
contribute to Common Nighthawk declines through higher rates of depredation on urban rooftop nests than nests in rural, natural habitats.
were captured by using cannon net traps in Bellvue, Colorado, USA; the National Wildlife Diseases Program, Animal and Plant Health Inspection Service, United States Department of Agriculture, assisted with the captures.
4-6: average lifespan, in years, of a wild American crow
Social learning spreads knowledge about dangerous humans among American Crows
Notably, the NS3 Thr249Pro substitution, suggested to be associated with increased virulence for American crows
(15), was not uniformly present in all the 2008-2009 isolates in Italy.
We also documented beak abnormalities in an additional 148 northwestern crows in south-central and southeastern Alaska and in 64 crows near Vancouver, British Columbia, and Puget Sound, Washington, a region where both northwestern crows and American crows
Among the larger numbers recorded this year - along with the evening grosbeaks, pine grosbeaks and common redpolls - were 731 house sparrows, 689 rock (Dove) pigeons, 533 dark-eyed juncos, 508 cedar waxwings, 478 starlings, 462 American tree sparrows, 396 American crows
, 383 tufted titmouse, 326 American goldfinches, 275 mourning doves, 252 snow buntings, 230 wild turkeys, 217 black-capped chickadees, 204 white-breasted nuthatches, 126 northern cardinals, 131 downy woodpeckers, 111 common ravens and 101 blue jays.
Each checklist is intended to help ornithologists track such trends as the expanding range of the Eurasian-collared dove and the diminishing number of American crows
, which have been hit hard by West Nile virus.
My guess is he's talking about American crows
, which go to large communal roosts at night," says Noah Strycker of Creswell, who has written for "Birds of Oregon: A General Reference.
From the start of the West Nile virus invasion of the United States, American crows
have developed severe symptoms and died by the hundreds, dropping on roadsides and at least twice on the White House lawn.
(Corvus brachyrhynchos) roost communally during the winter, often forming flocks of >1,000 birds (Emlen 1938, Stouffer and Caccamise 1991).
Previous research showed that feather pulp was slightly more efficacious than oral swabs for detecting WNV when the VecTest assay was used for corvids (21), and that 100% of feather pulp samples were positive among WNV-infected American crows
and blue jays (Cyanocitta cristata) (20).