156 Dawson, Bird Colonies of the Olympiades. [a^hi 



Of these twelve three, viz., Ccrorhinca monocerata, Ptijchoramphun 

 aleuticus, and Oceanodroma kaedingi, were never seen by daylight 

 save as unearthed from their nesting-l)urrows. 



Baird Cormorants, the Gulls, and the Oystercatchers are by no 

 means confined to the islands enumerated below, but are found 

 upon all the lesser rocks as well as upon the more rugged parts of 

 the mainland shore, — in short, wherever conditions are suitable. 

 The Oystercatchers do not colonize in the strict sense, and are 

 usually distributed at the rate of a pair to a rock, but the largest 

 islands may boast from three to a dozen pairs of them. The Baird 

 Cormorants have a single eye to the availability of a nesting spot, 

 stipulating only that it shall be upon the side of a wall, and as nearly 

 inaccessible as possible ; but whether affording shelter for one pair 

 or a hundred matters nothing. 



The Western Gulls occupy exclusively the southern members of 

 the Olympiades, and give way before Glaucous-wmgs from De- 

 struction Island northward. A slender strain of the darker bird, 

 however, reappears in the larger northern colonies of nesting 

 glaucescens, and their apparent interbreeding with the latter is 

 worthy of careful investigation. The Gulls, while preferably 

 nesting in colonies, nevertheless overflow^ by pairs and dozens 

 upon the smaller ])innacles, so that no exact account of their nesting 

 places is possible. 



The following species of non-breeding sea-birds appear to occur 

 regularly along this coast in summer, and are listed in the order 

 of their abundance, beginning with the most numerous: 



Marbled Murrelet {Brachyramphus marmoralus). 



Dark-bodied Shearwater (Pufjimis griseus). 



White-winged Scoter {Qidemia deglandi). 



Surf Scoter (Oidemia perspicillata) . • 



Harlequin Duck (Histrionicus histrionicus) . 



American Scoter (Oidemia americana). 



Holboell Grebe (Colymbus holboellii). 



Western Grebe {/Echmophonis occidentalis) . 



Loon (Gavia imber). 



So late as the 5th of June Pacific Divers (Gavia pacifica) were 

 found migrating northward in considerable numbers; as were also 

 Northern Phalaropes {Phalaropus lohaius). A flock of Heermann 



