Ecological Relations 



The optimum habitat of the Swainson's Warbler is a rich, damp 

 (but not wet) woods with deep shade and moderately dense under- 

 growth. This combination occurs in the physiographic areas in 

 which this species is nearly always found — namely, the floodplain 

 and swamp forests of the Atlantic and Gulf Coastal Plains and 

 certain plant associations of the mixed mesophytic forest of the 

 Southern Appalachians. When in swamps, the Swainson's War- 

 bler frequents those parts that usually are not inundated, but 

 occasionally on the Coastal Plain it may be observed foraging 

 along the wet margin of a swamp or in low wet spots that have 

 been left from receding floodwaters in floodplain forests. In such 

 situations, its foraging behavior on the ground may resemble that 

 of the Louisiana Waterthrush (Seiurus motacilla). Where inunda- 

 tion is present in a floodplain forest, it is usually the result of late 

 spring floods or heavy rains, after the birds have selected a breed- 

 ing territory in a dry section of woods. 



Whether on the Coastal Plain or in the mountains, this species 

 is usually near some major drainage system. The river valleys 

 provide moist conditions on the breeding grounds, as well as 

 "highways" for migration. 



In Coastal Plain forests, where most of my experience has been, 

 it is my observation that the Swainson's Warbler, more than its 

 closest avian associates, is restricted to the shadier part of the 

 forest. Species such as the Carolina Wren (Thryothonis ludo- 

 vicianus), the White-eyed Vireo (Vireo griseus), the Prothonotary 

 Warbler (Protonotaria citrea), the Hooded Warbler (Wilsonia 

 citrina), the Kentucky Warbler (Oporomis formosics), the Cardi- 

 nal (Richmondena cardinalis), and the Rufous-sided Towhee 

 (Pipilo erythrophthalmus) spend only a part of their time in parts 

 of the forest as shady as those frequented most of the time by the 

 Swainson's Warbler. The deep shade of the Swainson's Warbler 

 environment is the result of dense upper canopy, layer of lower 

 trees, and shrub strata. Herbaceous ground cover is absent in 

 most of the warbler's habitats, and where it occurs it is usually 

 of little consequence as a shade producer. 



The Swainson's Warbler lives mostly in the shrub stratum and 



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