Guide to North American Birds

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Photo: Bob Steele/Vireo

Blue-gray Gnatcatcher

Polioptila caerulea

A very small woodland bird with a long tail, usually seen flitting about in the treetops, giving a short whining callnote. Often it darts out in a short, quick flight to snap up a tiny insect in mid-air. Widespread in summer, its breeding range is still expanding toward the north.

Conservation status	Has expanded its breeding range through much of the northeast during the 20th century, and expansion may be continuing. Current population probably stable or increasing.
Family	Gnatcatchers
Habitat	Open woods, oaks, pines, thickets. Breeding habitat varies with region. In east, mostly in deciduous forest dominated by oak, ash, or maple, or in southern pine woods with understory of oak. In west, often in more scrubby habitat, including pinyon-juniper woods, chaparral, streamside trees, oak forest. Winters in wooded or brushy areas, often near water.

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Feeding Behavior

Forages actively in trees and shrubs. Searches for insects among leafy outer twigs of deciduous trees and on branches and trunk in pines. Takes most food while perched, also hovers to pick items from surface, and often flies out to catch insects that it flushes from foliage. Large insects are beaten against a branch before being eaten.

Eggs

4-5, sometimes 3-6. Bluish white, dotted with reddish brown. Incubation is by both parents, 11-15 days, usually 13. Young: Female broods young much of time at first, while male brings food; later, both feed nestlings. Young leave nest about 10-15 days after hatching. 1-2 broods per year.

Young

Female broods young much of time at first, while male brings food; later, both feed nestlings. Young leave nest about 10-15 days after hatching. 1-2 broods per year.

Diet

Mostly insects. Feeds on a wide variety of small insects, including leafhoppers, treehoppers, plant bugs, leaf beetles, caterpillars, flies, small wasps, and many others. Also eats many spiders.

Nesting

Male arrives first in breeding areas and sings to defend territory and attract a mate. Courtship involves male leading female around to potential nest sites. Nest site is in tree, more often deciduous. Nest saddled on top of horizontal limb of tree, less often in fork of horizontal limb; height above ground is quite variable, 2-80' up, but 20-40' may be typical. Nest (built by both sexes) is a compact open cup of grass, weeds, plant fibers, strips of bark, lined with plant down, animal hair, feathers. Outside of nest coated with spiderwebs and decorated with pieces of lichen, making nest well camouflaged.

Illustration © David Allen Sibley.
Learn more about these drawings.

Text © Kenn Kaufman, adapted from
Lives of North American Birds

Migration

Probably all in North America are migratory, with different individuals present in summer and winter. Some in Mexico and Bahamas may be permanent residents. Peak migration periods in many areas are April and September. May migrate by day.