An assertive bird of dry open country, the gray and lemon-yellow Cassin's Kingbird hunts flying insects from high perches. The bird’s scientific name translates to “vociferous tyrant,” and it fits this loud, aggressive songbird well. Males may attack large hawks that pass too close to the nest or battle rival kingbirds that enter the nesting territory. Cassin’s Kingbird resembles the widespread Western Kingbird but lacks that species’ white outer tail feathers and features a neat white throat that stands out against a stormy gray head and breast.
Walk or drive slowly through open habitat with scattered trees in the early morning, and listen for the rollicking dawn song or the emphatic ti-bew call of this rather noisy species. The birds perch prominently on large trees, bare limbs, or utility poles, which also helps with the search. These feisty birds are often active before dawn and through much of the day, though they may seek shade during extreme heat.
In 1826, naturalist William Swainson was the first to describe Cassin’s Kingbird to science, from a specimen collected in Mexico. Twenty-four years later, George Lawrence gave the bird its current English name, in honor of his friend John Cassin, a prominent Philadelphia ornithologist.
As with many birds of the American Southwest, Cassin’s Kingbirds are summer residents in the United States that migrate to Mexico for the winter. The species also has a large population in Mexico that does not migrate, a pattern known as “partial migration.” Other species that do this include the Rose-throated Becard, Mexican Whip-poor-will, Elegant Trogon, Buff-breasted Flycatcher, and Violet-crowned Hummingbird.
Cassin’s Kingbirds often sing at night, and are sometimes mistaken for nightjars and other night birds.
The ranges of Cassin’s and Western Kingbirds overlap geographically and partially in elevation. Competition for nest sites and foraging habitat appears to be minimal between the two species. Cassin's Kingbird nest success is higher, however, when Western Kingbirds are absent.
Flycatchers
