ALASKA YELLOW WAKBLEE. S'? 



662b. Dendroica aestiva rubiginosa (Pall.)- Alaska Yellow Warbler. 



The breeding yellow warblers of British Columbia and Alaska have 

 been segregated under this name. They migrate through California 

 and winter in Mexico, but the records of their movements can not be 

 separated from those of the allied varieties inhabiting these districts. 



663. Dendroica bryanti castaneiceps Eidgw. Mangrove Warbler. 



The mangrove warbler is not found in the United States, but occurs 

 in western Mexico and Lower California, where it may be found both 

 in winter and summer. 



664. Dendroica caerulescens (Gmel.). Black-throated Blue Warbler. 

 664a. Dendroica caerulescens cairnsi Coues. Cairns Warbler. 



The Cairns warbler breeds in the AUeghenies from Virginia (rarely 

 Pennsylvania) southward to northern Georgia. In North Carolina it 

 nests commonly at 3,000 to 4,500 feet above sea level, and in fall 

 migration individuals have been seen at 6,400 feet elevation. 



The records of migration and wintering of the black-throated blue 

 warbler make no distinction between the two forms, caerulescens and 

 cairnsiy hence in the following accounts of winter range and spring 

 and fall migration the two forms are treated as one. 



Breeding range. — The breeding range of cderulescens extends from 

 Newfoundland and northeastern Quebec through northern New Eng- 

 land and south in mountainous country to Pennsylvania. The bird 

 breeds rather commonly in the vicinity of Montreal, and not uncom- 

 monly westward to Michigan and northern Minnesota, in which State 

 it is found as far west as the forests extend. 



Migration range. — To the southward it is scarcely found west of the 

 Mississippi River, though it has been several times recorded in Iowa 

 and Missouri. Accidental occurrences have been noted at Lincoln, 

 Nebr., in Finney County, Kans., at Denver, Colo., and at Rio Mim- 

 bres and Rio Grande, N. Mex. The southwestern limit of the regular 

 range of the species is probably the mouth of the Mississippi River. 



Winter range. — The black-throated blue warbler occurs in winter 

 in the United States at Key West, Fla., where it is sometimes not 

 uncommon. At this season it is the most abundant of North Ameri- 

 can birds in Cuba, and is equally common in Haiti. In Jamaica it is 

 less common, and in the Bahamas rare, though very abundant in the 

 latter islands during the spring migration. While very abundant on 

 the south coast of Cuba, it is rare farther south, though it has been 

 taken at Little Cayman," Swan Islands,^ and Cozumel.^ The sole 

 record of its occurrence in Central America is that of a specimen 



«Cory, Auk, VI, p. 31, 1889. 



^Ridgway, Proc. U. S. Nat. Mus., X, p. 575, 1888. 



cKidgway, Proc. U. S. Nat. Mus., VIII, p. 564, 1885. 



