Black-throated blue warbler

Dendroica caerulescens

A rare female black-throated blue warbler was seen recently in St. George by Rick Fridell. The usual range of the black-throated blue warbler is northeastern Canada and the U.S., south into the Carolinas. The bird spotted in St. George was significantly off course.

This is a migration time for many birds. The black-throated blue warbler is a neotropical migrant. It feeds primarily on insects and insect larvae that it gleans from trees and shrubs. Winters find them south into Central and South America.

The male is easily identified in breeding plumage with its blue-gray back, white wing patch and white under parts. The female's breeding plumage is brownish olive to gray on the upper body. She has a white supercilium and a small white patch on the wing.

The female builds the nest and incubates 3 to 5 eggs from 12 to 13 days, with the altricial young fledging within 12 days.

Although rare in Utah, they are common in deciduous and mixed coniferous forests in their normal range, particularly in dense undergrowth. Backyard bird feeders in the northeast frequently see the black-throated blue warbler coming to suet feeders.

Rain forests are important wintering habitats. They are vulnerable to habitat loss due to deforestation.

Bill Fenimore is owner of the Layton Wild Bird Center, www.wildbird.com/layton and author of the Backyard Birds of Utah.