| Gnatcatchers | |
|---|---|
| Polioptila californica | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Aves |
| Order: | Passeriformes |
| Suborder: | Passeri |
| Superfamily: | Certhioidea |
| Family: | Polioptilidae Baird, 1858 |
| Genera | |
The 15-20 species of small passerine birds in the gnatcatcher family occur in North and South America (except far south and high Andean regions). Most species of this mainly tropical and subtropical group are resident, but the Blue-gray Gnatcatcher of the USA and southern Canada migrates south in winter. They are close relatives of the wrens.
These dainty birds are intermediate between "Old World warblers" and wrens in their structure and habits, moving restlessly through the 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 (esp. males) and long, regularly cocked, black-and-white tails. The skulking gnatwrens are browner, more thickset, and with proportionally shorter tails and longer bills.
The 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 behavior of several of the Neotropical species is essentially unknown.
A species new to science, the critically endangered Iquitos Gnatcatcher Polioptila clementsi, was first described in 2005. This species is a member of the Guianan Gnatcather Polioptila guianensis complex, which recently has been proposed split into three species (four w. the Iquitos Gnatcatcher), but not all authorities have accepted this (e.g. SACC). Furthermore, other groups should possibly be split, notably the Tropical Gnatcather Polioptila plumbea and Masked Gnatcather Polioptila dumicola complexes, but at present scientific papers on these matters are lacking.