What distinctive physical characteristic, besides the yellow belly, defines the Western Kingbird's tail structure?
A black, square-tipped tail with white edges
The Western Kingbird possesses several key plumage features that aid in identification, particularly when distinguishing it from closely related species. While the bright yellow belly is characteristic, a stable and key distinguishing feature relating to its tail structure is that it is black and square-tipped, prominently featuring white edges. This specific tail pattern contrasts with the tails of some congeners; for example, Couch's and Tropical Kingbirds are noted as possessing dark brown, notched tails. The presence of the black, square-tipped tail with white edges is a fixed trait marking the specific evolutionary path of *T. verticalis* and helps differentiate it even when facing confusion with other yellow-bellied species.
