Among the Corvidae, blue jay numbers are largest in the east, which coincides with the eastern woodland affinity of this species. Black-billed magpies occur in largest numbers in the west. The American crow population is largest in the eastern half of the study area. American crow numbers probably reflect the larger number of farmsteads, shelterbelts, and feedlots here which crows use extensively for feeding, nesting and roosting. Black-capped chickadee abundance is greatest in the eastern half of the study area, reflecting the general eastern affinity of this woodland species.
House wrens are also most abundant in the east.
Eastern bluebirds become virtually nonexistent west of 100 degrees W. longitude, and American robin numbers also decline west of that longitude. Gray catbird distribution appears to be related to the location of Riparian Forests along the Platte River, but northern mockingbirds are most prevalent in the west. The latter may reflect colonization of the Platte River by southwestern populations of this ubiquitous species of the southern United States. The center of abundance of the brown thrasher was in the western half of the study area. The occurrence of large numbers of brown thrashers in the west may be a reflection of habitat stability because this species is typically associated with eastern or southeastern scrub habitats.