Occasional Papers of the Museum of Zoology 7 



longer. Willows were in bloom on April 29. The ice in the river, 

 which of course was small at this place, broke up on April 26. 

 During the second week in May the willows and birches began 

 to send out vigorous buds, and small leaves had appeared by 

 May 15. A week later they were well leafed out. 



Vertebrate Habitats and Associations 

 Aquatic habitat aiui association: 



Rana cantabrigensis latiremis. Northern wood frog. Summer. 



Colymbus holbcelli. Holboel grebe. Summer. 



Gavia pacifica. Pacific loon. Summer (Blackwelder). 



Gavia stellata. Red-throated loon. Summer. 



Anas platyrhynchas. Mallard. Summer. 



Mareca americana. Baldpate. Summer. 



Nettion carolinense. Green-winged teal. Summer. 



Dafila acuta Izilzihoa. Pintail. Summer. 



Clangula clangula americana. Golden-eye. Summer. 



Charitanetta albeola. Bufflehead. Summer. 



Harelda hyemalis. Old-squaw. Summer. 



Histrionicus histrionicus pacificus. Harlequin duck. Summer. 



Oidemia perspicillata. Surf scoter. Summer. 



Anser albifrons gambeli. White-fronted goose. Summer. 



Branta canadensis hntchinsi. Hutchins goose. Summer. 



Lobipes lobatus. Northern phalarope. Summer. 



Pandion haliaetus carolinensis . Fish hawk. Summer. 



Streptoceryle alcyon caurina. Western kingfisher. Summer. 



Mustela vison ingens. Alaska mink. 



Ltitra canadensis canadensis. Canada otter. 



Fiber zibethicus spatulatiis. Northwestern muskrat. 



Castor canadensis canadensis. Canada beaver. 



Alces gigas. Alaska moose. 



In interior Alaska there are two principal rivers, the Yukon 

 and the Kuskokwim, each fed by numerous tributaries, some of 

 which are of large size. Small streams and creeks abound, and 

 most of these flow throughout the year, though they are frozen 

 over in winter. Those streams which flow from the region of 

 active glaciers on the north side of the Alaska Range carry much 

 fine mud in suspension during the summer, and for this reason the 

 Yukon and the main Kuskokwim are muddy streams. The 



