HABITAT SELECTION BY THE WESTERN KINGBIRD IN WESTERN NEBRASKA - A HIERARCHICAL ANALYSIS

This study examined the relationship between habitat structure and habitat use by the Western Kingbird (Tyrannus verticalis) in western Nebraska using hierarchical analysis. Multivariate statistics compared habitat used by Western Kingbirds with a null model of random, unused habitat at multiple scales: macrohabitat (habitat type and territory) and microhabitat (nest tree and nest site). Western Kingbirds exhibit different patterns of habitat use at different spatial scales. They are highly selective at the macrohabitat scale, using only a subset of the available habitat types. Used habitat types have large, widely spaced cottonwood trees with greater grass cover, while unused habitat types have smaller, more closely spaced trees with less grass cover. In contrast, Western Kingbirds are less selective within the macrohabitat scale. There are few significant differences between used and unused territories-only maximum canopy height was significantly different. Western Kingbirds are highly selective at the microhabitat scale, and nest in only a subset of the available trees-larger, taller trees with more available perches. This pattern of nest tree use is consistent between used study sites, even in the face of some inter-site differences in habitat structure. In addition, nest-site location is similar between used study sites and among nest trees. Habitat use by Western Kingbirds in western Nebraska is consistent with a hierarchical view of habitat selection in which Western Kingbirds use different sets of selection criteria at different scales, arriving within the habitat type and then selecting territories, nest trees and nest sites.