Nest is 5 to 20 feet above ground in the crotch of a shrub or small tree (Potter et al. 1980), in a cluster of branches on a horizontal limb (Griscom and Sprunt 1957), and rarely on the ground (Ehrlich et al. 1988). In the coastal plain, nest is often placed in vines or tangles (Fussell 1994). Occasionally a nest of another species will be used (Ehrlich et al. 1988).

NATURE SERVE GLOBAL HABITAT COMMENTS:

BREEDING: Various mature and second-growth wooded habitats. Deciduous and mixed deciduous-coniferous second-growth forests, alder swamps, old growth forests with regenerating trees (e.g., around tree-fall gaps), willow thickets, small groves; low, damp, second-growth deciduous and mixed floodplain forests and river swamps; most abundant in mature deciduous forest stands, but also may occur in young woods less than 15 years old; requires closed canopy and prefers dense midstory and understory and well-developed undergrowth; use of pole-stage stands apparently varies geographically (Cruickshank 1979, Crawford et al. 1981, Harrison 1984, DeGraaf 1985, Bushman and Therres 1988, Sherry and Holmes 1997). Nests usually are placed in an upright fork of a deciduous understory sapling, shrub, or tree, occasionally in a vine tangle or old vireo nest; nest usually is about 1-6 m above ground, sometimes as high as 28 m.

Southeastern U.S.: Primary breeding habitats in the Piedmont and Coastal Plain are bottomland hardwoods and swamps, especially in extensive stands. In the mountains this species occurs in hardwoods along streams, usually where it is open and not heavily wooded. Birds are less frequent in medium-growth hardwood forests away from water. Hamel et al. (1982) described the key habitat requirements for breeding as hardwood forests near water. They provided the following details on habitat use and suitability in Virginia, North Carolina, South Carolina, Georgia, and Florida. The following five vegetation types used by this species in five physiographic provinces (Mountains, Sandhills, Piedmont, Inner Coastal Plain, and Outer Coastal Plain) are considered in order of suitability: elm-ash-cottonwood is suitable at the sapling-poletimber stage, optimal at the late-successional sawtimber stage; southern mixed mesic hardwoods and oak-gum-cypress are suitable at both the sapling-poletimber stage and sawtimber stage; oak-hickory and cove-hardwoods are marginal habitat at the sapling-poletimber stage and suitable at the sawtimber stage. In all cases, shrubs and midstory are used for all activities (feeding/foraging, nesting, perching, roosting, and singing), whereas the overstory is used for feeding/foraging, perching, roosting, and singing, but not nesting. No specific vegetation sizes were given. Yellow birch is significantly preferred for nesting, and fledging success is significantly higher in yellow birch than beech or sugar maple; this result is especially true for large, old trees. Nest concealment from predators accounts for these patterns (Crew and Sherry, unpubl. data). Northeastern and north-central U.S.: In New York, breeders use low, damp woods and have been found in mixed woodland with a considerable growth of pine and hemlock; in the Adirondacks, nest sites often occur where spruces predominate. In Ohio, Michigan, and other sections of the Midwest, this species inhabits the maple, elm, ash, and pine-oak association of the larger, more mature swamp forests, although it is sometimes found among similar trees and brush in the larger upland woods. In the far Northwest, it shows a decided preference for willow trees and alder thickets. In Maine, the bird is found in hardwood or mixed deciduous and coniferous woodlands; these may be low, damp situations but birds are also often found in the second-growth of trees and brush of the dry sandy plains. Alder and willow thickets bordering streams and ponds are used here also (Bent 1953). In New Hampshire, redstarts are especially abundant in second-growth edge and in old-age northern hardwood forests, but they also occur in other moist woodlands, mixed hardwood-conifer woods, and alder and willow thickets. Here, this species breeds from near sea level to above 3000 ft (910 m), where the highest elevation hardwoods grade into conifers in the White Mountains (Sherry and Holmes 1994).

Quantitative habitat measures have been documented in a few studies. Sabo (1980) measured habitat selection in the White Mountains of New Hampshire and listed the following parameters: mean elevation - 830 m, canopy height - 10.4 m, canopy coverage - 74%, conifer foliage volume - 38%, conifer foliage cover (0-2 m) - 20%, broad leaf foliage volume (>5 m) - 92%, and dbh of live trees - 11 cm. Collins et al. (1982) quantified habitat in north-central Minnesota: ground cover - 67.7%, shrub cover - 70.7%, canopy cover - 66.3%, canopy height - 14.5 m, conifers - 4.7%, and numbers of species of trees per 0.04 ha circle - 4. In addition, Collins et al. (1982) surveyed vegetation and recorded the numbers of trees in different size classes: 10.7 (7.5-15 cm), 10.7 (15.1-23 cm), 8.2 (23.1-30 cm), 4.6 (30.1-38 cm), 1.1 (38.1-53 cm), 0.3 (53.1-68 cm), and 0.1 (>68.1 cm). Sherry and Holmes (1985, unpubl. data) documented significant preferences for deciduous stands of trees along a deciduous-coniferous gradient.

NON-BREEDING: In winter and migration, habitats include various kinds of forests, woodlands, scrublands, and thickets, including mangroves; uses a wide variety of agricultural habitats (e.g., cacao, citrus, pine plantations, mango, and sun and shade coffee plots) (Robbins et al. 1992). Primary wintering habitats are mainly in broadleaf evergreen woods and thickets, such as hammocks and mangroves (Hamel et al. 1982). In Venezuela, mangroves were a transitory habitat, used primarily in the middle of the wintering period by a low number of females (Lefebvre et al. 1992). In Jamaica, widespread in various habitats and are regularly found in drought-deciduous dry limestone forest, citrus, wet limestone forest (evergreen), gardens, and residential areas (Holmes et al. 1989, Holmes and Sherry 1992); they tend to be most abundant at lower elevations (Sherry, pers. comm.). Redstarts in Jamaica segregated by sex, with males in mangroves and females mainly in contiguous scrub habitat (Parrish and Sherry 1994). In the Dominican Republic, habitats include strand vegetation, mangroves, scrub, disturbed dry forest, riparian, urban, disturbed wet forest, mesic forest, and wet forest (Arendt 1992). In the Yucatan Peninsula, redstarts prefer moist forest, but also inhabit dry forest, wet forest, field and pasture, and acahual; late-successional forest stages are clearly preferred (Lynch 1992); redstarts were the third most common species found in mature semi-evergreen forest (after hooded [WILSONIA CITRINA] and magnolia warblers [DENDROICA MAGNOLIA]); were also found in mid-successional Acahual although less commonly so, and were rarely found in field/pasture habitat (Lynch 1989).

NATURE SERVE STATE HABITAT COMMENTS: