Hylocichla mustelina (Gmelin)
Bellbird, Song Thrush, Swamp Angel, Swamp Robin, Wood Robin (Terres 1980).
Breeder. Common in spring, summer, and fall in all regions. In Gulf Coast region, occasional in winter. MODERATE CONSERVATION CONCERN.
Medium-sized bird (18-20.5 cm [7-8 in.]; Howell and Webb 1995). Sexes similar; upperparts bright reddish brown, especially on head, neck, and back; cheek patch whitish with fine dark streaks and a conspicuous white eye ring; underparts white with distinct dark spotting on breast, sides, and throat. Loud, sweet, flutelike song is calm, unhurried, and peaceful, and consists of three- to five-note phrases with most notes differing in pitch and each phrase usually ending with a complex trill (Sallabanks et al. 1998). Calls include a rapid pit-pit-pit (Terres 1980). No subspecies recognized (Roth et al. 1996).
Breeds from southeastern North Dakota and central Minnesota across northern United States and adjacent southern Canada to Nova Scotia; south to eastern Texas, the Gulf Coast, and northern Florida; and west to eastern South Dakota, central Nebraska, central Kansas, and eastern Oklahoma (AOU 1998). Winters from southeastern Mexico to northern Colombia (Howell and Webb 1995). In Alabama, common in spring, summer, and fall in all regions. In Gulf Coast region, occasional in early winter (Jackson 2001a).
Breeds in deciduous or mixed forests with dense tree canopy and fairly well-developed understory, especially where moist (Roth et al. 1996). Bottomlands and other rich hardwood forests optimal (Sallabanks et al. 1998). Also frequents pine forests with deciduous understory, and well-wooded residential areas (Hamel et al. 1982). Thickets and early successional woodlands generally not suitable (Roth et al. 1996). In migration and winter, uses woodlands of various types from humid lowland to arid or humid montane forest, also scrub and thickets (Sallabanks et al. 1998).
Forages on, or near, ground and diet consists of a variety of insects, spiders, myriapods, sowbugs, snails, and earthworms. Also consumes fruits of spicebush, dogwood, Virginia creeper, blackberries, elderberries, pokeweed, and mulberries (Terres 1980).
LIFE HISTORY AND ECOLOGY:
Returns to breeding grounds in April and May; territorial and socially monogamous during breeding (Roth et al. 1996). Nest built in crotch, or saddled on branch, of shrub, sapling, or large tree, usually less than six meters (20 feet) above ground (Terres 1980). Primarily female constructs a cup nest lined with rootlets and composed of grasses, bark strips, mosses, leaves, and mud; a piece of paper or white cloth often conspicuously incorporated into nest. A clutch of two to five (usually three to four) bluish-green eggs are laid between April and July. Female incubates eggs for 12-14 days and both parents feed young, which leave nest when 12-13 days old. Young become independent when 21-31 days old. Replacement clutches produced if nests fail and two broods are usually attempted. Frequently subjected to brood parasitism by brown-headed cowbirds (Roth et al. 1996, Sallabanks et al. 1998).
BASIS FOR STATUS CLASSIFICATION:
Breeding Bird Survey data indicate a significant population decrease over much of distribution since late 1970s (Roth et al. 1996). The key habitat requirement is mature forest with an understory of deciduous shrubs or saplings. Habitat degradation and fragmentation in breeding and wintering areas are greatest threats. Habitat size is as important as habitat type because nest predation and nest/brood parasitism rates are higher in small woodlots and along the edges of larger tracts than in the interior of large tracts. Fragmented forests may be population sinks with populations sustained by immigration from larger, unfragmented forest tracts. Brown-headed cowbird is a serious threat, causing significant population declines throughout much of distribution. Loss of tropical forests also may contribute significantly to regional declines in temperate North America (Sallabanks et al. 1998). Priority designation in Alabama based on Partners In Flight (PIF) scores for three factors: distribution of nonbreeding populations, threats to nonbreeding populations, and population trend. Has relatively narrow nonbreeding distribution, and nonbreeding populations threatened because of expected human alteration of tropical, broadleaved forests. Breeding Bird Survey data demonstrate a large population decrease in the Central Hardwoods Bird Conservation Region, and possible or moderate population decreases in the Appalachian Mountains, Piedmont, and Southeastern Coastal Plain Bird Conservation Regions. Additionally, in Appalachian Mountains, severe deterioration in the future suitability of breeding conditions is expected. Breeding Area Importance scores indicate highest relative abundance in Appalachian Mountains and Piedmont and in high relative abundance in Central Hardwoods and Southeastern Coastal Plain (PIF 2002).
Paul D. Kittle