At one time these two types of orioles where both considered the same, northern orioles, but testing has shown that there is enough of a difference between the two to separate them into different species. Orioles, it would appear, did not get the memo because they often mate across the species where their ranges cross, creating Bullock's Baltimore hybrids.
Bullock's orioles are primarily insect eaters. They find their prey by scouring the trees and bushes for spiders, caterpillars and other insects. Their preferred habitat is open woodland especially when it is next to a river or stream. This makes sense, since we spotted quite a few of these birds, and took these photos, in Celebration Park, which is located adjacent to the Snake River near Boise, ID.