Overview
Dusky Warbler: Small, dark warbler with gray-brown upperparts, gray-streaked underparts, distinct white eyebrow, and faint eye-ring. The tail is slightly round-tipped. Brown legs and feet. Forages on ground, in trees. Constantly flicks wings. Weak fluttering direct flight with shallow wing beats.
Range and Habitat
Dusky Warbler: Native of Asia; casual on islands off western Alaska, and in fall off south coastal Alaska and in California. Preferred habitats include mountain thickets and forests.
Old World Warblers and Gnatcatchers (Sylviidae)
ORDER
The one hundred eighteen families in the taxonomic order PASSERIFORMES (pronounced pas-ser-i-FOR-meez) include a variety of small perching birds such as the kinglets as well as large birds such as the crows and jays.
FAMILY TAXONOMY
In the Sylviidae (pronounced sil-VEYE-uh-dee) family, a group with a nearly worldwide distribution, there are two hundred sixty-six species of Old World warblers and gnatcatchers in thirty-three genera. (It should be noted that some authorities split this large family into several smaller families).
NORTH AMERICA
In North America, twenty-one species in four genera of the Sylviidae family have occurred. Counted among these species are the spry gnatcatchers and the Arctic Warbler.
KNOWN FOR
The Blue-gray Gnatcatcher is known for its feisty, active mannerisms. The cocked and spread tail, scolding call notes, and thin black eyebrow of the male give this tiny bird an angry appearance.
PHYSICAL
Members of the Sylviidae are small birds with fairly long legs, and strong feet that suit their arboreal nature. They have thin, medium length bills and rather short wings.
COLORATION
The gnatcatchers are mostly gray and white with black markings on the face, crown, and tail. Most species also have white eye rings and white markings in the tail. The Old World warblers are dull colored birds that are brown or olive on the upperparts and whitish on the underparts, some species with streaks and most with wing bars.
GEOGRAPHIC HABITAT
In North America, the Sylviidae are mostly birds of mild climates although one species, the Arctic Warbler, breeds in Alaskan thickets although the core of its range is in Siberia. Other Old World warblers that occur in North America are also primarily found in Asia and only occur as vagrants to the west coast. The resident members of this family other than the Arctic Warbler are the gnatcatchers; birds of the eastern deciduous forests and arid habitats of the southwest.
MIGRATION
The Blue-gray Gnatcatcher migrates to the southern United States and Mexico during the winter.
HABITS
The Old World warblers and gnatcatchers do not nest in colonies but often join flocks comprised of assorted species of small birds that forage together for protection from predators. Members of the Sylviidae forage for invertebrates by gleaning them from the vegetation of trees and bushes.
CONSERVATION
In the United States, the California Gnatcatcher is listed as threatened because of destruction of its shrubland habitat in southern California. Although most other members of this family are doing well, the Iquitos Gnatcatcher is critically endangered. Only described in 2005, this little known species is very rarely seen in its threatened, white sand forest habitats.
INTERESTING FACTS
Like the fantails of Asia and the Slate-throated Redstart, gnatcatchers often spread their tails to flash the white feathers while foraging. This may be a strategy to scare insect prey out into the open from their hiding places.