Kirtland's warbler, also known in Michigan by the common name jack pine bird, or the jack pine warbler, is a small songbird of the New World warbler family (Parulidae). Nearly extinct just years ago, populations have recovered due to the conservation efforts of the Kirtland's Warbler Conservation Team and its members. The birds require large areas, greater than 160 acres, of dense young jack pine for breeding habitat. This habitat was historically created by wildfire, but today is created through the harvest of mature jack pine, and planting of jack pine seedlings.
Region
Great Lakes region and the Bahamas
Typical Environment
Breeds primarily in the jack pine plains of Michigan, with smaller breeding populations in Wisconsin and Ontario, using dense, young jack pine on sandy outwash soils. It requires large contiguous tracts where trees are roughly 1.5–5 m tall and 5–20 years old. During migration it uses shrubby, early-successional habitats across eastern North America. In winter it occupies dry to semi-moist scrub and coppice habitats in the Bahamas, often where fruiting shrubs are abundant.
Altitude Range
Sea level to 500 m
Climate Zone
Other
Ease of Keeping
Beginner friendly: 1/5
Once on the brink of extinction, Kirtland's warbler has rebounded thanks to intensive habitat management and cowbird control, and it was delisted from the U.S. Endangered Species Act in 2019. It breeds almost exclusively in large tracts of young jack pine stands in the Great Lakes region. The species is conservation-reliant, needing ongoing management to maintain suitable early-successional habitat.
Female
Kirtland's warbler found in northwest Ohio on May 14, 2010, on the shores of Lake Erie where migrant warblers occasionally appear in spring, perhaps before crossing into Ontario.
This Lower Peninsula jack pine stand was slightly too young in 2002, but by 2008 made good breeding habitat. By 2015–2020, the mature trees would form a forest nearly 20m high, rendering it unsuitable for Kirtland's warbler breeding.
Temperament
secretive and territorial
Flight Pattern
short rapid wingbeats
Social Behavior
Monogamous pairs defend breeding territories in dense young jack pine. Nests are placed on or near the ground under low pine cover. Brown-headed Cowbird parasitism is common without management, and control of cowbirds has been crucial to reproductive success.
Migratory Pattern
Seasonal migrant
Song Description
The male’s song is loud, ringing, and buzzy, often rendered as a series of clear, descending phrases. Calls include sharp chips given from cover when alarmed.
Plumage
Males have slate-blue to bluish-gray upperparts with black streaking on the back and bright yellow underparts with heavily streaked flanks; females are duller gray-brown above with paler yellow below. Both sexes show a broken white eye ring giving a ‘spectacled’ look. The plumage is clean and crisp in spring, becoming more worn and subdued later in the season.
Diet
Primarily feeds on insects and other arthropods, including caterpillars, beetles, and spiders gleaned from foliage and low branches. During winter it supplements with small fruits and berries, especially in the Bahamas. Occasional foraging on the ground occurs in open patches within dense scrub.
Preferred Environment
Forages in dense young conifers on the breeding grounds, working low to mid-levels of vegetation. In winter it uses scrubby thickets and coppice with abundant insect prey and fruiting shrubs.
