Guide to North American Birds
Conservation status Endangered. Always known as a scarce bird with a limited range, Kirtland's Warbler apparently began to decline seriously in the 1960s; census numbers dropped from 502 singing males in 1961 to only 201 in 1971. Through most of the 1970s and 1980s, the annual counts hovered around 200 males, twice dropping as low as 167. Since 1990 the numbers have gradually increased. The tally of singing males topped 1,000 for the first time in 2001, increased to 1,700 by 2007, and hit 2,000 in 2012. Although these are still dangerously low numbers for a songbird, the trend is encouraging. Conservationists are helping the bird by providing more habitat (controlled burning creates the stands of young jack pines needed by the warbler) and by controlling the numbers of parasitic cowbirds in the nesting areas.
Family Wood Warblers
Habitat Young jack pine; winters in dense understory of pines. Breeds only in large stands of young jack pines from 5-25' tall. Jack pine grows on sandy soils, and regenerates only after fires. In migration, seen in thickets and deciduous trees. During winter, rarely seen, found only in dense undergrowth of pine forests of the Bahamas.
One of our rarest songbirds, Kirtland's is a relatively large warbler that forages slowly, close to the ground, wagging its tail up and down. It nests only in stands of young jack pines in central Michigan, a habitat that grows up only briefly after fires, and its nests have been heavily parasitized in recent decades by Brown-headed Cowbirds. Controlled burning to create more habitat, and control of cowbird numbers, have helped the warbler somewhat, but it is not necessarily out of danger yet.

Photo Gallery

Feeding Behavior

Forages for insects near the ground and in lower parts of pines and oaks. Will hop on ground to probe for insects. Gleans insects from pine needles and other vegetation, and occasionally takes items while hovering. Solitary in its foraging in winter.


Eggs

4, sometimes 3-6. Buff or pinkish-white with brown spots at larger end. Incubation is by female only, 13-15 days; males feed females on nest during incubation. Up to 70% of nests are parasitized by Brown-headed Cowbirds in areas where there is no control of cowbirds by humans. Young: Fed by both parents. Young leave nest at age of 9 days, do not fly well at first. Parents continue to feed young up to 6 weeks. Usually 1 brood, rarely 2.


Young

Fed by both parents. Young leave nest at age of 9 days, do not fly well at first. Parents continue to feed young up to 6 weeks. Usually 1 brood, rarely 2.

Diet

Mostly small insects, some berries. In summer, eats many insects, including sawfly adults and larvae, grasshopper nymphs, moths, and flies. Adults also feed on pine sap and blueberries. May feed soft berries to young. In winter in the Bahamas, feeds on insects and small fruits.


Nesting

Males arrive on breeding grounds in mid-May, a few days before the females, and establish large territories. Tend to be loosely colonial (lone pairs are rare), and males tend to return to the same colony in which they previously nested. Males sometimes have more than one mate. Nest: Placed on ground in sandy soil close to pine. Nest (built by female) is open cup made of grass, sedge, pine needles, oak leaves, lined with rootlets, hair, moss, and fibers.

Illustration © David Allen Sibley.
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Text © Kenn Kaufman, adapted from
Lives of North American Birds

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Migration

Arrives on nesting grounds mostly in mid-May, and gradually departs during August and September, migrating to the Bahamas. Very seldom seen in migration, probably because of the needle-in-a-haystack challenge of finding such a rare bird.

See a fully interactive migration map for this species on the Bird Migration Explorer.

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Songs and Calls

Low pitched, loud, bubbling, and rising at the end.
Audio © Lang Elliott, Bob McGuire, Kevin Colver, Martyn Stewart and others.
Learn more about this sound collection.