Least Flycatcher

As its name implies, the Least Flycatcher is the smallest of the flycatchers that breed in New Hampshire. Like its relatives in the confusing genus Empidonax it is a dull gray-green bird with wingbars and an eye ring. As is the case in this group, song is the best basis for identification, which in the case of the Least is an oft-repeated “che-bek.” The closest similar song is the softer “che-buk” of the Yellow-bellied Flycatcher, but thankfully the two species rarely occur in the same habitat. 

Least Flycatchers are birds of hardwood forests and edges, and rarely occur in shrubby areas (used by Willow and Alder Flycatchers) or dense coniferous forest (Yellow-bellied). As a result, they are probably the most widely distributed of the group in the state, ranging from coastal lowlands to the North Country and White Mountains. This is not to say that they can be found everywhere, since Least Flycatchers usually cluster together in loose “colonies.” Research suggests that these clumped territories are the result of females preferring to select mates from a group, and perhaps even having ready access to males that are not their primary mate. Solitary males, even if in suitable habitat, often fail to attract a mate.

Although they use a variety of forested habitats, Least Flycatchers tend to occur in more open areas or those with lots of saplings. Examples include regenerating timber harvests, forest clearing, riparian corridors, and edges. Declines in this species across eastern North America are often attributed to gradual forest maturation since the 1960s. In the absence of periodic selective logging or similar disturbance, sapling densities decline to the point where flycatcher clusters gradually fade away and presumably relocate elsewhere. If there are fewer suitable habitat patches it may be harder for males to reach the densities needed to attract females, with lower productivity as the inevitable result.