Bullock's orioles are also called western orioles. The male Bullock's is distinguished from the male Baltimore oriole by its orange cheeks, large white wing patches, and different tail pattern. The female Bullock's has a by a grayer back and whiter belly than the female Baltimore oriole. Their songs are somewhat different, but much interbreeding takes place, and these two types of orioles are now regarded as conspecific. Orioles do most of their singing on their breeding grounds, and are quieter on their wintering grounds.
Orioles build nests on their breeding grounds.
They don't do this anywhere else. A nest provides a safe place to lay eggs and raise young. Orioles eat many more insects on their breeding grounds, and much more fruit and nectar in the tropics. On the breeding grounds they need lots of protein to make eggs and feed growing babies. Please answer ONLY ONE question in EACH e-mail message.