Despite its common name, the Eastern Kingbird breeds abundantly west of the Mississippi River, and its range extends to the Pacific Ocean. In the Great Plains and Far West it may breed sympatrically with 1 or 2 other species of kingbirds.
Kingbirds are well known for their aggressive nature.
Pairs are monogamous, maintain territories while breeding, and if both survive to the following breeding season, usually remate and reuse former territories. Nonetheless, extra-pair copulations and intraspecific brood parasitism may be common. The Eastern Kingbird overwinters in Amazonia. While there, it maintains different social and feeding behaviors than are seen during the breeding season. Most individuals travel in flocks and forage on fruit, returning to North America to begin laying eggs by late May and early June.