Small flycatcher, extremely similar to several other species. Generally shy and inconspicuous; breeds in spruce forests often near boggy areas. Migrants tend to be found in denser wet areas within woods. Olive-greenish above with distinctive yellow wash on throat and belly. Black wings with bold white wingbars. Nearly identical to Western Flycatchers, but limited range overlap. Within range, main confusion species is Least Flycatcher. Bright yellow throat and belly is usually enough to identify Yellow-bellied Flycatcher, but some worn birds can be very similar. Song is similar to Least Flycatcher ("chebek") but more slurred, with a soft buzzy tone. Not frequently repeated like Least Flycatcher. Soft whistled call note, "pwee," unlike Least's sharp "whit" call.