The Ovenbird breeds in dry upland forests, usually deciduous or deciduous/coniferous, from British Columbia to Newfoundland and southeast to the northern parts of the Gulf Coast states [Van Horn and Donovan 1994 (BNA)]. Nests are built on the ground, starting in mid-May in Vermont, and there is one brood per year [Ellison 1985]. Ovenbirds walk on the forest floor and feed from the substrate, mainly on invertebrates [Van Horn and Donovan 1994 (BNA)]. They winter in dry upland forests or second growth throughout most of Central America, the Caribbean Islands and southern Florida [Van Horn and Donovan 1994 (BNA)]. Breeding territories may be clustered [Stenger and Falls 1959], while they are thought to occupy solitary territories in winter [Faaborg and Arendt 1984].
Migration is assumed to be mostly nocturnal, this species frequently being noted in tower kills at night, e.g. Orange Co., Florida [Taylor 1972]. Ovenbirds are noted in a wide variety of habitats during migration, spring migrants pass through Florida from mid-April to late May and generally arrive in New England during the first week of May [Ellison 1985]. Fall migration peaks in mid-September in the northeast, with analysis of banding recoveries suggesting that birds breeding east of the Appalachian Mountains follow the Atlantic flyway to Caribbean Island wintering grounds [Van Horn and Donovan 1994 (BNA)].
Ovenbirds exhibit area sensitivity, requiring intact interior forests in the 100-885 hectare range to breed successfully. It is unclear whether increased brood parasitism by cowbirds and predation at the edges cause males to avoid edge territories, females to avoid pairing with edge males, or edge nests to fail more frequently [Van Horn and Donovan 1994 (BNA)]. The Breeding Bird Survey [Robbins et al. 1989] estimates a yearly population decrease of 1% from 1978-1987, perhaps due principally to loss and fragmentation of both Temperate and Neotropical forests.
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Observations
Many wintering Ovenbirds are territorial in forest habitat, while breeding birds are a well-known indicator species for intact, unfragmented forest. During spring migration in the Conte Refuge, the more wooded C sites were significantly preferred. Ovenbirds arrived in period 2 in all states, generally peaking from periods 3-5.
In CT, the southernmost state, numbers dropped sharply in period 5; in our northernmost state of VT the peak was latest (period 4). |
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