The tropical kingbird (*Tyrannus melancholicus*) is a large, bold flycatcher with one of the widest distributions of any bird in the Western Hemisphere, ranging from the southwestern United States all the way through Central and South America to Argentina. It is a strikingly handsome bird, with a heavy, broad-based bill, a grayish head marked with a dusky mask through the eye, an olive-green back, and a brilliant lemon-yellow belly and breast that make it easy to identify when seen well. Like other kingbirds, it is intensely aggressive and fearless in defending its territory, readily mobbing much larger birds — including hawks, falcons, and vultures — with loud, chattering calls and relentless aerial pursuit. Its voice is a distinctive, rapid twittering trill that is often the first clue to its presence, and it frequently calls from conspicuous open perches such as treetops, utility wires, and fence posts, from which it launches aerial sallies to snatch flying insects. In the United States it is primarily a rare but regular visitor to southern Arizona and the Texas coast, but throughout the tropics it is an abundant and familiar bird of forest edges, open woodlands, roadsides, and towns, where it thrives in close proximity to human activity.