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.
One of the principal factors limiting plover recovery is egg and chick predation (USFWS 2007), especially by Common Ravens (Corvus corax) and to a lesser degree American Crows
are known to herd sparrows into the sides of buildings where the stunned sparrows become easy prey.
In the contiguous United States, the American crow
(Corvus brachyrhynchos) is easily the most common.
Two wildlife biologists equipped with binoculars, clipboards and tally "clickers" search the urban skyline for the first flights of American crows
making their way to a stand of trees nestled on a hillside in downtown Troy.
Among birds, American crows
(Corvus brachyrhynchos) and European starlings (Sturnus vulgaris) seem particularly susceptible to infection by West Nile virus, based on reported cases of mortality.
Nearly 90% of the 4,304 West Nile-infected birds in 2000 were American crows
, which are highly susceptible to the virus and develop high levels of viremia, followed by blue jays (5%).
Increasing reports of WNV infections in American crows
, other avian species, and mosquitoes are being accompanied by reports of neurologic disease caused by WNV in humans, horses, and other mammals.
(Corvus brachyrhynchos) are acutely sensitive to West Nile virus (WNV) infection, and crow mortality has been used in WNV surveillance to monitor enzootic transmission.
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.
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.
Declining and not rebounding were American crows
, American robins, Eastern bluebirds, black-capped chickadees, Carolina chickadees, and tufted titmice, she and her colleagues report in the June 7 Nature.
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.
(Corvus brachy-rhynchos) are talkative, territorial and devoted to their families.
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.