Saw my first one of these at LEGO Land in Oceanside, California. I’ve seen several in Mexico since. It’s a fun bird to watch. Unlike most birds its size, which hop from branch to branch every few seconds, the Cassin’s Kingbird is patient. It’ll sit on a branch for minutes, slowly (well, slow for a bird) swiveling its head back and forth, waiting for right moment to spring forward and swallow an unsuspecting insect. It’s also a fun bird to listen to. It has, sort of, a construction-worker-whistling-at-a-passing-babe whistle, followed by a series of staccato cha-cheer-sounding chirps.
(Sorry the picture is blurry. I need one of the telescopic birdie cameras….)