16 NORTH AMERICAN FAUNA 61, FISH AND WILDLIFE SERVICE 



they probably immigrated southward or southwestward to the 

 Aleutian district. There are, of course, a great many others 

 of northerly distribution whose general range is such that the 

 route of the population movement is uncertain. In the group 

 here listed it will be seen that the Aleutian district has drawn 

 heavily from the fauna that characterizes the northern portion 

 of the continent from northern Alaska across to Hudson Bay. 

 Lemmings, Arctic hares, the jaegers, Sabine's gull, and others, 

 came straight down the Bering Sea coastal strip. 



It will be noted that not all of the birds just listed actually 

 nest in the Aleutian district. 



SOUTHERN AND SOUTHEASTERN AVIFAUNA 



SCIENTIFIC NAME COMMON NAME 



Phalacrocorax auritus cincinatus Double-crested cormorant 



Olor buccinator Trumpeter swan 



Anas strepera Gadwall 



Lams glaucescens Glaucous-winged gull 



Brachyramphus marmoratum marmoratum Marbled murrelet 



Synthliboramphus antiquum, Ancient murrelet 



Ptychoramphus aleutica Cassin's auklet 



Cerorhinca monocerata Rhinoceros auklet 



Megaceryle alcyon caurina Belted kingfisher 



Troglodytes troglodytes ssp. (in part) Winter wren 



Ixoreus naevius Varied thrush 



Vermivora celata lutescens Orange-crowned warbler 



Pinicola enucleator flammula Pine grosbeak 



Leucosticte tephrocotis ssp Gray-crowned rosy finch 



Loxia curvirostris sitkensis . . Red crossbill 



Passerculus sandwizhensis ssp Savannah sparrow 



Passerella iliaca ssp Fox sparrow 



Melospiza melodia ssp Song sparrow 



Some of these listings give us a clear demonstration of the 

 route of influx into the Aleutian district, by way of closely related 

 subspecies in a series extending along the coastal strip of southern 

 and southeastern Alaska. Such examples are the song sparrows, 

 fox sparrows, and winter wrens in particular. The fox sparrows 

 present an interesting distributional picture. It is the dark coastal 

 unalaschcensis group that has worked along the coast and fully 

 occupied the suitable habitats as far as the eastern Aleutians. 

 But the bright-colored eastern type has come down from the 

 northeast and, at the base of Alaska Peninsula, this type has made 

 contact with the coastal forms. 



Naturally, there could be error in the interpretation of faunal 

 immigration just cited, because complexities may have intervened 



