1910] Grinnell—Birds: Alaska Expedition, 1908. 419 
COMPOSITION OF THE PRINCE WILLIAM SOUND 
AVIFAUNA; DISCUSSION OF ITS ORIGIN. 
The animal and plant hfe of the Prince William Sound 
region clearly belongs to two life zones, the Hudsonian and 
Alpine-Arctic. The former is practically comecident with the 
timbered areas, which extend from sea-level to an altitude vary- 
ine from 1,000 to 1,600 feet, and is confined to a relatively 
narrow tract borderme the sea shore and extending up the 
(See plate 34.) The Alpine-Arctic, or treeless, zone 
covers the tops of the mountains on the islands, and the interior 
land-mass which surrounds the Sound. 
valleys. 
The birds of the region appear to be groupable zonally as 
follows: 
1. Land-birds believed to breed in the Hudsonian zone of the 
Prince William Sound district: 
Canachites canadensis atratus 
Accipiter velox 
Archibuteo lagopus sancti-johannis 
Haliaeétus leucocephalus alascanus 
Bubo virginianus lagophonus 
Ceryle aleyon cawrina 
Dryobates pubescens glacialis 
Selasphorus rufus 
Bmpidonax trailli alnorum 
Pica pica hudsonia 
Cyanocitta stelleri stelleri 
Corvus corax principalis 
Corvus brachyrhynchos caurinus 
Pinicola enucleator flammnula 
Loxia leucoptera 
Passerculus sandwichensis alaud- 
TNUS 
Tunco hyemalis hyematis 
Melospiza melodia kenaiensis 
Melospiza lincolni gracilis 
Passerella iliaca sinwosa 
Hirundo erythrogaster palmeri 
Tachycineta thalassina lepida 
Vermivora celata lutescens 
Dendroica aestiva rubiginosa 
Dendroica townsendi 
Wilsonia pusilla pileolata 
Cinclus mexicanus unicolor 
Nannus hiemalis pacificus 
Certhia americana montana 
Penthestes rufescens vivax 
Regulus satrapa olivaceus 
Regulus calendula grinnelli 
Hylocichla guttata guttata 
Txoreus naevius meruloides 
2. Land-birds believed to breed in the Alpine-Arctic zone of 
the Prince William Sound district : 
Lagopus rupestris kelloggae 
Leucosticte tephrocotis littoralis 
Acanthis linaria linaria 
Anthus rwbescens 
Osgood (N. A. Fauna no. 19, 1900, p. 16, foot-note) has called 
attention to the fact that the humid Pacifie Coast belt of Alaska 
