The Burmese bushtit is sometimes treated as conspecific with the black-browed bushtit. Birds distinctive to this zone are the California thrasher, the American bushtit, and California condor. Birds unique to this zone are the California thrasher, bushtit, and California condor. The "black-eared" bushtit was formerly considered a separate species ("P. melanotis"). The pygmy bushtit ("Aegithalos exilis") is a species of bird in the bushtit family Aegithalidae. The bushtit and Bullock's oriole will suspend their nests from the tips of slender branches. The sooty bushtit ("Aegithalos fuliginosus") is a species of bird in the family Aegithalidae. In North America, it is referred to simply as "bushtit". Several bushtit species display cooperative breeding behavior, also called helpers at the nest.