Icterus bullockii
- General Description
- Bullock's Orioles are bright, flashy birds in all plumages. Mature males are deep orange, with black wings, back, and tail tips, and white wing-patches.
- They have black caps, black lines through each eye, and black throat patches.
- Females and first-year males are yellow where mature males are orange, but are whitish underneath.
- They lack the large white wing-patches, but do have two white wing-bars on each side.
- First-year males can be distinguished from females by their black throats and eye-lines.
- Habitat
- The typical breeding habitat of Bullock's Orioles in Washington is forested streamside.
- They primarily inhabit hardwood trees and can often be found in large cottonwoods, willows, and oaks.
- Freshwater wetlands, irrigated farms, orchards, shrub-steppe, suburban areas, and other edge habitats are also used if there are suitable trees for nesting.
- During migration, Bullock's Orioles can be found in a wide variety of open woodlands, including urban parks.
- Their winter habitat requirements are not well known, but appear similar to that of breeding season.
- Behavior
- While Bullock's Orioles may form small flocks during migration and winter, they generally forage alone.
- They forage mainly in the tree canopy, where they glean food from the foliage and occasionally fly out to catch aerial prey.
- They also forage in open country (shrub-steppe, for example) and sometimes on the ground, especially later in the breeding season.
- Nesting
- Bullock's Orioles are monogamous and nest solitarily, although nests are often grouped together, which may be more a factor of patchy breeding habitat than colonialism.
- Pair bonds typically last for a single breeding season.
- The nest is often located in a willow, cottonwood, or other hardwood tree, and is a pendulous basket suspended from a thin branch that commonly hangs over water.
- The female picks the nest site and weaves the nest, but the male may help with construction.
- The nest often appears gray, and is made of hair, twine, grass, and wool, lined with plant-down, hair, or feathers.
- The female typically incubates 4 to 5 eggs for about 11 days and then broods the young after they hatch.
- Both parents bring food to the young, which leave the nest after about 14 days.
- Family groups typically stay together after the young fledge, and may join with other families in post-breeding flocks.
- Diet
- Bullock's Orioles eat a diet of small invertebrates (including many caterpillars), ripe fruit (especially cherries), and some nectar.
