Host-feeding patterns of a mosquito species to a large extent determine whether it is an enzootic or epidemic vector or plays no role at all in transmission of a pathogen. Traditional serological methods of blood meal analysis combined with polymerase chain reaction-based methods have allowed fine scale studies of the feeding patterns of potential vectors of West Nile virus. Geographic variation in host-feeding patterns of mammalophilic species appear to reflect local variation in abundance host. In recent investigations, mosquito species in New Jersey and New York that fed mainly on white-tailed deer generally took blood meals from dogs in Tennessee. In contrast, ornithophilic mosquitoes tended to feed on the same species of birds regardless of geographic location and host abundance. The American robin, Northern Cardinal and Brown-headed Cowbirds were common birds at several geographic locales; albeit, the frequency of feeding on these species is greater than would be expected based on their local abundance. In comparison, few blood meals are taken from the American crow despite its high local abundance. The implications of mosquito host-feeding patterns and host abundance on the acquisition and transmission of West Nile virus is discussed.