The dusky flycatcher, Empidonax oberholseri, breeds in the western United States and western Canada. The species migrates south to warmer areas for the winter, with most individuals moving to southern Arizona or northern Mexico. The dusky flycatcher is a common breeder in Utah, where it prefers open and semi-open habitats, particularly areas with dense brush that are located near water.
The nest is built above the ground in a bush or small tree. A clutch of three or four eggs is laid and then incubated by the female alone for 12 to 17 days. Both parents tend the young, which leave the nest at two to three weeks of age.
The dusky flycatcher is active during the day. It eats insects, which it captures in the air or gleans from vegetation.