The olive-sided flycatcher, Contopus cooperi, breeds in Alaska, Canada, much of the United States (with the exception of the southeastern United States), and part of northern Mexico. The species is migratory, moving to South America, Central America, and southern Mexico for winter. The olive-sided flycatcher is moderately common in much of Utah during its summer breeding season. It prefers woodland and forest areas, especially areas where standing dead trees are present.
The nest is above ground in a tree. A clutch of three eggs is laid and then incubated by the female alone for about two weeks. The young fledge at about two or three weeks of age.
The olive-sided flycatcher is active during the day, often perching on a dead tree to sing and watch for food. Flying insects, mainly bees, make up the bulk of the diet.