Bay-Breasted Warbler (Dendroica castanea)

County List:

Rule:

Forested or Mixed Forested/Nonforested Landscapes

      (Spruce/Fir (Sm Saw or Lg Saw or Uneven))
      or (Mixed Upland Conifer (Sm Saw or Lg Saw or Uneven))
   containing:
      Stand/Gap Openings

Habitat List:

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Literature:

Habitat: In Houghton and Keweenaw Counties, this species seeks out cool, rather dense patches of boreal, second-growth, mesic coniferous forest dominated by white spruce and balsam fir, with scattered eastern white pine, birch, and aspen. Such forests grow on sandy ridges between the Lake Superior coast and interior bogs. In Alger Co. and some places outside Michigan, it occasionally inhabits mature, mesic mixed forest, but spruce or balsam fir or both are always major components. Nests are invariably in conifers. The Rabbit Bay nest was situated near the trunk, 29 feet up in a spindly 34 foot balsam fir (12.7 cm dbh). The nest was composed entirely of loosely woven, brown needles of the eastern white pine.

The fact that mesic coniferous forest is scarce and local in the state, being virtually restricted to low-lying coastal strips in the northern UP, is sufficient to explain the rarity and northern, somewhat coastal distribution of the warbler. Although the secondary habitat, mesic mixed forest, is more widespread, only locally does it contain a high enough percentage of spruce and balsam fir; where it does, the resultant patches probably should be termed mesic conifer forest.

Habitat: Breeding: Northern coniferous or mixed forests, especially in young trees along ponds, streams, in bogs or forest clearings.

Special Habitat Requirements: Early coniferous second growth of trees 6 to 10 feet tall.

This is a characteristic warbler of spruce forest in eastern Canada in summer. Its numbers vary from year to year and are likely to increase quickly during population explosions of the spruce budworm or other forest pests.

Habitat: Woodlands, conifers in summer. Usually breeds in northern coniferous forest, in thick stands of spruce and fir. Where spruce is not found, will nest in deciduous or mixed second-growth woods of birches, maples, firs, and pines.

Diet: Mostly insects, berries. In breeding season, eats a variety of insects, including beetles, flies, moths, caterpillars, leafhoppers, and grasshoppers; also Virginia creeper berries and mulberries. May eat many spruce budworms when that insect is at epidemic numbers.

Nest: Site is on a horizontal branch of a dense spruce, hemlock, birch, or other tree, 4-40 feet above the ground. Nest is a large, open cup, either loosely built or compact, made of grasses, lichens, roots, mosses, and protruding conifer twigs; lined with bark strips and hair.