YELLOW-RUMPED WARBLER (Dendroica coronata) MYWA Sample size: 2,941 |
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The northern and eastern "Myrtle" race of the Yellow-rumped Warbler breeds mainly in mature coniferous or coniferous-deciduous forest from Alaska to Labrador, and south in this habitat to the Great Lakes, thence east to northern Pennsylvania and Massachusetts [Hunt and Flaspohler 1998 (BNA)]. Nests are usually on horizontal evergreen branches at any height [Harrison 1975], usually single brooded. Myrtle Warblers feed on invertebrates in the breeding season, gleaning conifers or catching insects in flight [MacArthur 1958]. On the east coast, Myrtle Warblers winter from the southern Great Lakes and southern New England, south through the Gulf coast, eastern Central America and the Caribbean Islands [Hunt and Flaspohler 1998 (BNA)]. Winter flocks occupy almost any open habitat, feeding on invertebrates and fruit [Remsen et al. 1989]. A common food item on the Atlantic coast is the fruit of the bayberry or waxmyrtle, hence the name "Myrtle" warbler.
Migration is primarily nocturnal; spring migrants leave Puerto Rica in late-March to early-April [Raffaele 1989], peaking in New England and southeast Canada from late-April to mid-May [Francis and Cooke 1986]. Fall migration is late and much more extended, with peak movements in New England in mid-October [Veit and Petersen 1993], but not reaching Puerto Rica until late-November [Raffaele 1989]. Almost any open habitat is used by migrants, usually in flocks, and there is some evidence of continuing migration southwards during fall and winter. Males tend to winter further north while females predominate in Florida and southwards [Hunt and Flaspohler 1998 (BNA)].
In the northeast U.S., breeding was restricted to mountainous areas in the early 1900's, but extended south with later reforestation and conifer plantations [Laughlin and Kibbe 1985, Foss 1994]. Myrtle Warblers breed at a rather low but variable density, and Breeding Bird Survey data (1966-1994) for North America showed increases of 1.8% per year. There were decreases in eastern Canada, but greater increases in New England [Sauer et al. 1996].
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Observations
The Myrtle Warbler (hence the code MYWA) is the northern and eastern sub-species of the Yellow-rumped Warbler, the only warbler to winter extensively on the coasts of SE and S New England. Their ability to digest the waxy coating of persistent winter berries allows them to migrate early up the Connecticut River valley during periods 1 to 3. Greatest densities were detected in period 2 in CT and period 3 in MA. In all states, numbers declined to near zero in periods 4 and 5 (i.e. by late May).
There was not much variance in numbers between A, B and C sites, except that early large flocks (20's and 30's/transect) in CT and MA caused individual peaks. Later in the season, in C sites and also further N, fewer large flocks were noted. |
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MYWA Map
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