Phainopeplas are common in the Sonoran and Colorado Deserts, where they breed from February into April. With the onset of summer heat, these birds leave the desert and take up residence in oak and sycamore canyons of Arizona and California--here they breed again, but ornithologists do not know if the same birds breed twice. Furthermore, Phainopeplas behave differently in the two habitats. Desert birds form pairs that fiercely defend their territory. In woodlands, birds form loose colonies of 3-15 pairs. These colonies are defended by the groups. In the desert, Phainopeplas specialize in eating mistletoe fruit. Many mistletoe seeds pass through the birds and establish themselves as parasites on a variety of desert trees and bushes. This stable resource may be one reason for the behavioral differences between desert and woodland populations (Chu and Waisberg 1999).


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