Phainopeplas feed on mistletoe in winter, and on other berries (and insects) in spring through fall. At most times of year, they are territorial, often perching for long periods to watch for intruders as they guard berries, nests, and territorial boundaries. Sometimes they nest in small colonies, and after breeding they often form large flocks. Most winter at lower elevations in deserts and move in warmer months to higher elevations.