As were most of the other birds, because without grouse there was no income, without income there were no gamekeepers, and without the keepers the populations of crows and foxes, which prey on young birds, shot up.
Data from individually marked populations of crows in New York State and Oklahoma (K.J. McGowan, Cornell University, Ithaca, NY; A. Clark, State University of New York-Binghamton, Binghamton, NY; and C.L. Caffrey, National Audubon Society, Ivyland, PA) show that these populations are experiencing important declines after the initial WNV outbreak.
Correction: September 30, 2000, Saturday An article on Sept. 21 about efforts by Singapore to control its population of crows characterized the country's size incorrectly.
Proving once again that crows are smarter than humans, the house crow is a beautiful example of avian exploitation: no populations of house crows are known to exist independently of humans and our ubiquitous "trash heaps", "rubbish tips" or "garbage dumps".
Populations of American crows were most consistently affected with a substantial cumulative impact in six of ten states.
Disease-mediated inbreeding depression in a large, open population of cooperative crows.
The greatest impact was observed in the population of American crows, which declined by as much as 45%.
According to the 2011 census, the population of Old Crow was 245, with 86% identifying as Vuntut Gwitch'in.
Wheeler et al. [ 27] used the same method, in combination with seroprevalence, dead bird surveillance and susceptibility data and found that, besides American Crows, populations of House Finches (Carpodacus mexicanus), Black-crowned Night Herons (Nycticorax nycticorax), Western Scrub Jays (Aphelocoma californica) and Yellow-billed Magpies (Pica nuttalli) were particularly affected by WNV.
This not only increases the population of pigeons, but also that of crows and ravens, who seem to be favored targets for mosquitoes carrying West Nile, as a number of dead crows are found every year infected with this virus.
The phenomenon can, however, be understood by analogy with the well-known result that increasing sex bias decreases the effective size of populations (Wright 1931; Crow and Dennison 1988; Caballero 1994; Hartl and Clark 2007).
