The nest, a neat cup, is usually placed in a vertical fork of a branch in a small tree or sapling. The three to five eggs are incubated for 13 to 15 days. The least flycatcher's breeding range stretches from western Canada to Nova Scotia and south in the Appalachians to Tennessee and North Carolina. Empidonax minimum is fairly common across much of Pennsylvania, except for the southeast, where it is absent. In autumn, adults migrate ahead of juveniles to wintering grounds in Mexico and Central America.
Phoebes breed statewide in Pennsylvania, except in heavily urbanized areas.
They eat a variety of insects, including small wasps, bees, beetles, flies and moths. They often take prey from vegetation and from the ground, and they eat seeds and berries. The female builds a nest out of mud, moss, leaves, grass and hair, tucking the cup-shape structure into a sheltered spot beneath a rock ledge, against a stone wall, on a bridge beam or barn or porch support. A pair may use the same nest several years in a row. The female lays four or five eggs and incubates them for around 16 days.