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Morphological Description of American Crow, Corvus brachyrhynchos, Populations in Southern Quebec

Ludwig, Antoinette, Begras-Poulin, Michel, Lair, Stephane, Belanger, Denise
Canadian field-naturalist 2009 v.123 no.2 pp. 133-140
Corvus brachyrhynchos, West Nile virus, adults, crows, discriminant analysis, gender, monitoring, mortality, prediction, public health, sex determination, summer, Quebec
The American Crow has always been a much scrutinized bird in North America but, since the emergence of West Nile Virus (WNV) in North America in 1999, public health authorities’ attention to it has been raised another notch. In Québec, like everywhere else in North America, part of the WNV surveillance programme was based on detection of WNV mortality in crow populations. During the summer of the 2005 surveillance season, we followed an age and gender determination protocol, as well as a morphological measurement protocol, on dead crows sent in for WNV status determination, to improve our knowledge of the crow population in Québec. Statistical analysis of the measurements revealed that age and gender were important factors in the morphological characterisation of the American Crow. Bill depth and head-to-bill length appeared as the most important morphological variables for gender prediction through a discriminant function analysis. We also realized that, in adult age groups, our WNV positive carcasses had lower mean weights than carcasses that tested negative for WNV, in adult age groups.