Gray Catbirds breed in dense shrubs, vines, saplings, forest edges and clearings, roadside hedges and some thickly shrubby suburban gardens [Cimprich and Moore 1995 (BNA)]. They are usually double-brooded, the nest placed in dense vegetation, usually 1-2 m above the ground [Cimprich and Moore 1995 (BNA)]. Catbirds forage from the ground to the tops of trees, eating a wide range of invertebrates and fruit [Harcus 1973]. The breeding range reaches a northern limit from south British Columbia to Nova Scotia, extending south to east Texas and north Florida, excluding the immediate Gulf coast [Cimprich and Moore 1995 (BNA)]. The breeding range partly overlaps the winter range, which is on the Atlantic coast south of southern New England to Florida, and west and south around the Gulf coast to Panama and the western Caribbean Islands [AOU 1998]. Winter habitat in the U.S. is in shrubby areas, often near water [Hamel 1992], and south of the U.S. includes more forest and plantations, as well as scrub. Winter diet is dominated by fruit e.g. [Greenberg 1992], and both sexes defend separate winter territories [Rappole and Warner 1980].
Migration is nocturnal, indicated by restlessness in flight cages and the number of recorded tower kills [Graber et al. 1970]. Migration stopover habitat resembles breeding and winter habitat, and diet includes up to 81% fruit in fall [Martin at al. 1951]. Spring migrants depart from Central America in March/April, most reaching New England in May [Veit and Petersen 1993]. Fall migration in New England is difficult to separate from post-breeding dispersal to the coast, occurring from mid-August through October. Migrants pass south through Bermuda from mid-September to early November [Amos 1991]. In late September through October, migrants cross the Gulf coast to Yucatan, Mexico and the Greater Antilles [Marsh 1979].
Long-term data from the Breeding Bird Survey (1966-1991) indicate generally stable populations in New England, but recent significant decreases (post 1981) in both southeast U.S. and eastern Canada. Migrants are frequently killed at towers by night, and also on roads by day, due to their habit of low flights between hedgerows. A breeding preference for more shrubby areas and second growth may benefit catbirds as fragmentation, clearcuts and urban sprawl reduce eastern forest cover. However, in the largely coastal winter habitat, the loss of scrub, thickets, farmland and hedges to dense housing construction is likely to be increasingly deleterious [Cimprich and Moore 1995 (BNA)].
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Observations
This migrant species reaches its normal northern range limit within the study area, and is a non-forest resident during the breeding season. Interestingly, many catbirds wintering in Central America are noted as rain forest canopy foragers. During spring migration, A sites were overwhelmingly preferred (543/916 records). Also CT detected a significantly high 547 catbirds. Thus the riverine, Silver Maple dominated forests of the A sites in CT were the preferred forest habitat within our study area.
Gray Catbirds were first recorded at A sites in period 2, then B and C sites in period 3. Numbers increased to peak in periods 4 and 5. |
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