The Bullock’s Oriole hybridizes extensively with the Baltimore Oriole in the Midwest where their ranges overlap. Seasonally monogamous, their breeding season lasts from May until July.
Bullock’s Oriole males and females sing different songs. Before and during nest-building, the female sings regularly and may sing more than the male. Mated pairs weave deep, pendant baskets made of bark, fine grass fiber and animal hair. The interior is lined with down, hair and moss, and three to six eggs are laid. Both sexes rear the young and defend the nest from predators and parasites.
Bullock’s Orioles prefer habitat edges, riparian corridors, open deciduous woodland and scrub forests of cottonwood, pecan and willow. In dry areas, they prefer salt cedar and mesquite. Their diet consists of insects, berries and nectar. In California, eucalyptus trees are major sources of nectar.