Guide to North American Birds
Conservation status Current numbers probably stable. Because it inhabits shrubby second growth in both summer and winter, not as vulnerable as some warblers to loss of habitat.
Family Wood Warblers
Habitat Clearings, thickets, slashings, undergrowth. Breeds in brushy northern habitats, including dense shrubbery in old deciduous woods clearings, brushy cut-over lands, lowland thickets of raspberry and blackberry tangles, or bog and marsh edges; often in temporary habitats, growing up after fires or clearcuts. In winter in the tropics, lives in low, dense thickets and overgrown fields in lowlands and foothills.
Often elusive and hard to see well, the Mourning Warbler sings a repetitious chant from thickets and raspberry tangles in the north woods. This bird lives near the ground at all seasons, foraging in low brush and in the forest understory even during migration; it tends to be solitary, not readily joining flocks of other warblers. It got its name because the extensive black throat patch of the male suggested to pioneer naturalists that the bird was dressed in mourning.

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Feeding Behavior

During the breeding season, forages primarily in shrubs within a few feet of the ground; hops while feeding on ground. Sometimes makes short flights to catch flying insects. Generally feeds alone rather than joining flocks.


Eggs

3-4, sometimes 5. Creamy white with brown spots or blotches. Incubated by female only, about 12 days. Male feeds female on nest during incubation. Young: Both parents feed nestlings. Young leave the nest after 7-9 days. Care of fledglings may continue for another 4 weeks or more.


Young

Both parents feed nestlings. Young leave the nest after 7-9 days. Care of fledglings may continue for another 4 weeks or more.

Diet

Probably mostly insects. Details of the diet are poorly known, but has been seen foraging for caterpillars, beetles, and other insects; also eats spiders. In winter in the tropics, sometimes feeds on the protein bodies from the leaf-bases of young cecropia trees.


Nesting

Details of the breeding behavior are not well known. Male sings to defend nesting territory; during territorial boundary encounters with rival males, he may bob violently, flip wings outward, and fan his tail. Nest: Usually placed on ground next to shrub at base of weeds in raspberry or blackberry briars, or among fern, goldenrod, or grass tussocks. Also sometimes in bush within a couple of feet of the ground. Nest (probably built by both sexes) is an open, bulky cup made of leaves, with a core of weeds and coarse grasses, lined with fine grass and hair.

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

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Migration

In spring, apparently moves north overland through Mexico and Texas, rather than crossing the Gulf of Mexico like many other migrants; evidently retraces same route in fall. Migrates relatively late in spring and early in fall.

  • All Seasons - Common
  • All Seasons - Uncommon
  • Breeding - Common
  • Breeding - Uncommon
  • Winter - Common
  • Winter - Uncommon
  • Migration - Common
  • Migration - Uncommon

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

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Songs and Calls

Loud, ringing, musical song, teedle-teedle, turtle-turtle, the last pair of notes lower.
Audio © Lang Elliott, Bob McGuire, Kevin Colver, Martyn Stewart and others.
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How Climate Change Will Reshape the Range of the Mourning Warbler

Audubon’s scientists have used 140 million bird observations and sophisticated climate models to project how climate change will affect this bird’s range in the future.

Zoom in to see how this species’s current range will shift, expand, and contract under increased global temperatures.

Climate Threats Near You
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Climate threats facing the Mourning 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.