Tyrannus vociferans, commonly known as the Cassin's Kingbird, is native to the southwestern United States, Mexico, and extending into Central America. It is found primarily throughout regions such as Southern Arizona, New Mexico, Texas, and down through much of Mexico into northern Central America.

Cassin's Kingbird typically inhabits open areas with scattered trees, savannas, and edges of woodlands. They are often found in thorn scrub, mesquite, and other semi-arid environments. These birds prefer altitudes ranging from lowlands to approximately 2000 meters, often near agricultural lands and suburban areas where tall trees and utility poles provide vantage points for foraging.

Cassin's Kingbird is primarily an insectivore, feeding on a variety of insects that it catches in flight. It utilizes its perching strategy on high points to survey its territory and launch aerial sallies to capture prey. Beyond insect consumption, this species occasionally feeds on fruits and berries, adapting its diet to the availability of resources throughout the year. The Cassin's Kingbird typically nests in trees, preferring secluded and sheltered locations to guard against predators.