Primarily found breeding in only a small area in Michigan, the Kirtland's Warbler is restricted to nesting in habitats containing young jack pines. An endangered species, the best way to see one is to take one of the tours offered by the U.S. Fish and Wildlife Service or the U.S. Forest Service. The town of Roscommon, MI, celebrates the return of the Kirtland's Warbler with guided tours and a warbler parade.
Kirtland's WarblerDendroica kirtlandii
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 Michigan, a habitat that grows up only briefly after fires, and its nests are heavily parasitized by Brown-headed Cowbirds. Controlled burning to create more habitat, and control of cowbird numbers, have helped the warbler somewhat, but its total population in most recent years has remained below 1,000.
Field MarksBluish gray above, streaked with black; yellow below, with black spots or streaks confined to the sides. Male has a blackish mask. Female is grayer, lacks mask. In autumn, browner. Persistently jerks tail; no other gray-backed warbler does this.
Size6" (15 cm)
VoiceSong, loud and low-pitched for a Dendroica, resembles Northern Waterthrush's song; at times suggests House Wren's. Typical song starts with three or four low staccato notes, continues with rapid ringing notes on a higher pitch, and ends abruptly.
RangeNorth-central Michigan, nesting in loose colonies in an area about 100 miles long, 60 mile wide. Winters in Bahamas.
MigrationArrives on nesting grounds mostly in mid-May, and gradually departs during August and September, migrating to the Bahamas. Almost never seen in migration, probably because of the needle-in-a-haystack challenge of finding such a rare bird.
HabitatYoung 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. In winter, rarely seen, and only in dense undergrowth of pine forests of the Bahamas.
FeedingDiet: 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. Feeds soft berries to young. In winter in the Bahamas, feeds on insects and small fruits.
Behavior: Forages for insects near the ground and in lower parts of pines and oaks. Will hop on ground to probe for insects. Gleans adult insects and larvae from pine needles and other vegetation, and occasionally takes items while hovering. Solitary in its foraging in winter.
NestingMales arrive on breeding grounds in mid-May, a few days before the females, and establish large territories. Tends 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.
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 percent of nests are parasitized by Brown-headed Cowbirds.
Young: Fed by both parents. Young leave nest at age of 9 days. Parents continue to feed young up to 6 weeks. Usually 1 brood, rarely 2.
ConservationEndangered. Surveys found fewer than 200 pairs as recently as mid-1980s, but some counts in early 1990s topped 400 pairs. Now dependent on humans to provide habitat and control cowbird numbers.