Polioptilidae – Gnatcatchers

The Polioptilidae (Gnatcatchers & Gnatwrens) are a family of small passerines. The twenty species occur in North and South America (except for the far south and the high Andean regions). Most species of this mainly tropical and subtropical group are resident, but the Blue-grey Gnatcatcher of the United States and southern Canada migrates south in winter. They are close relatives of the Troglodytidae (Wrens).

These small birds are intermediate between Old-World warblers and wrens in their structure and habits, moving restlessly through foliage seeking insects. The gnatcatchers are mainly soft bluish grey in colour, and have the typical insectivore’s long sharp bill. Many species have distinctive black head patterns (especially males) and long, regularly cocked, black-and-white tails. The skulking gnatwrens are browner, more thickset, and with proportionally shorter tails and longer bills.

Slate-throated Gnatcatcher Polioptila schistaceigula	Masked Gnatcatcher Polioptila dumicola
Cuban Gnatcatcher Polioptila lembeyei	California Gnatcatcher Polioptila californica
All photographs in this text courtesy of ©Dubi Shapiro

They are distributed from North to South America, with the exception of the far south and high Andean regions. Gnatwrens typically occur in the undergrowth of dense, often humid, forest, while gnatcatchers, depending on the species involved, occur in anything from dry scrubby habitats (e.g. the California Gnatcatcher) to the canopy of humid Amazonian forest (e.g. the Guianan Gnatcatcher). The North American species nest in bushes or trees, but the breeding behaviour of several of the Neotropical species is essentially unknown.

Blue-grey Gnatcatcher Polioptila caerulea

White-lored Gnatcatcher Polioptila albiloris

These insectivores often forage in groups, and usually with the tail cocked or flicking animatedly. They are constantly on the move, and use their tails to balance as they twist and turn on a perch, then jump or flutter off to another in search of prey. The songs of the three genera differ; Ramphocaenus produce a slow, whistled trill. In Microbates it is a series of whistled notes, though their harsh scolding is more often heard. Singing Polioptila species intersperse whistles with their normal high wheezy or whiny twitters.