The split was recognized until 2023, when the American Ornithologists’ Union and International Ornithological Congress again lumped both species due to a lack of consistent vocal, genetic, morphological differences and extensive hybridization across much of their range.

[6] DNA testing in 2014 confirmed a new field mark, involving the extent of buffy edging on the secondaries, to reliably distinguish this species from the yellow-bellied flycatchers.

In Pacific birds, the ptsick or ptik note has the first syllable higher-pitched than the second—this was previously seen as the only difference between their calls and those of the "Cordilleran" flycatcher (Sibley 2000).

The male's typical position call is a loud and distinctive pit pete[citation needed] or tse-seet, but some give a "rising tsweep" or a "slurred tseeweep".

They fulfill an important role in keeping insect populations in check, particularly mosquitoes, and they also eat caterpillars and spiders.