Arctic Warbler
Arctic Warbler
Phylloscopus borealis
At a Glance
Along willow-lined streams in Alaska in summer, the song of the Arctic Warbler is unmistakable: a slow trill, with an insistent or hammering sound. When the bird hops into view among the branches, it is less distinctive, plain olive and whitish with a pale eyebrow. In fall, the Arctic Warbler crosses the Bering Strait and migrates south in Asia.
All bird guide text and rangemaps adapted from Lives of North American Birds by Kenn Kaufman© 1996, used by permission of Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Category
Old World Warblers and Gnatcatchers, Perching Birds
IUCN Status
Least Concern
Habitat
Forests and Woodlands, Shrublands, Savannas, and Thickets, Tundra and Boreal Habitats
Region
Alaska and The North
Behavior
Flitter
Population
82.000.000
Range & Identification
Migration & Range Maps
Alaskan birds winter especially in the Philippines, also in nearby areas of southeast Asia and Indonesia. Unlike some other Alaskan breeders, this species almost never strays southward in the New World.
Description
4 3/4" (12 cm). Plain above and below, with obvious whitish eyebrow. Compare to Tennessee Warbler, which is rare in Alaska.
Size
About the size of a Sparrow
Color
Brown, Gray, Green, White, Yellow
Wing Shape
Long, Rounded
Tail Shape
Square-tipped
Songs and Calls
A quick trill, introduced by zick or zick-zick-zick. The call is also zick or zirrup.
Call Pattern
Flat, Undulating
Call Type
Buzz, Chirp/Chip, Rattle, Trill
Habitat
Willow scrub. In Alaska, breeds in dense low thickets (4-10' tall) of willow, dwarf birch, or alder, mainly along streams. In Eurasia, breeds in similar habitat, but also in open forest of conifers mixed with deciduous shrubs.
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Behavior
Eggs
6-7, sometimes 5. White, finely dotted with brown. Incubation is by female only, 11-13 days.
Young
Both parents feed nestlings. Young leave nest about 12-14 days after hatching. 1 brood per year.
Feeding Behavior
Forages very actively among the foliage of bushes and trees, examining twigs and leaves for insects. Sometimes hovers to glean insects from foliage. Flies out to catch insects in mid-air, and may do so repeatedly when midges or mayflies are swarming.
Diet
Mostly insects. Diet in North America is not well known. In Eurasia, feeds on a wide variety of insects, especially beetles, mosquitoes, flies, leafhoppers, caterpillars, true bugs, mayflies, sawflies, also many others. Also eats some spiders and snails.
Nesting
Nesting behavior in Alaska not well known; information here includes data from Eurasia. Male sings to defend nesting territory; in aggressive encounters between males, they may flap wings slowly while singing. Nest site is on ground, usually in mossy ground cover under dense shrubs or in crevice among roots, sometimes tucked into side of grass tussock. Typically well hidden. Nest (thought to be built by female) is a domed structure with the entrance on the side; made of grass, weeds, moss, leaves, lined with fine grass.
Climate Vulnerability
Conservation Status
The small population in Alaska is probably stable; could be affected by loss of habitat on wintering grounds.
Climate Threats Facing the Arctic Warbler
Choose a temperature scenario below to see which threats will affect this species as warming increases. The same climate change-driven threats that put birds at risk will affect other wildlife and people, too.