Crow Trends in West Virginia
In striking contrast, early-winter populations of American Crows in West Virginia (as indicated by the number of birds counted/party-hour) have increased dramatically over the same time period, especially since 2002, and an apparent 5-fold increase since the mid-1990s (left-click on the graph below to enlarge). Also, crows appear to be relatively more abundant in West Virgina by an order of magnitude.
The same general trend is also evident when we graph the actual number of birds counted (below).
The reason(s) for the dramatic differences in population trends between the two adjacent regions is not obvious, but would certainly seem to merit additional investigation. Are the birds wintering in these regions from different breeding grounds in which susceptibility to WNV differs? Have crows shifted their wintering grounds westward for reasons unrelated to WNV? Is WNV less prevalent in West Virginia than in the Mid-Atlantic States? As is so often the case, this comparison raises many more questions than answers.