SEABIRDS OF ALASKA, BRITISH COLUMBIA, AND WASHINGTON 



87 



are no Brandt's cormorant colonies in the San 

 Juan Islands or Strait of Juan de Fuca. Yet 

 Jewett et al. (1953) reported colonies at Bell- 

 ingham Bay and on Lopez and Matia islands. 

 We have observed juvenile Brandt's cor- 

 morants in the San Juan Islands during the 

 summer. This species may be particularly sus- 

 ceptible to human disturbance, since all three 

 areas listed above are heavily used in the sum- 

 mer for recreation. 



Pelagic Cormorant (Phalacrocorax 

 pelagicus) 



The distribution of breeding colonies of the 

 pelagic cormorant is strongly determined by 

 the availability of the steep cliffs on which it 

 constructs its nest. This is the only common 

 cormorant in southeastern Alaska. Through- 

 out its extensive range, this species is gener- 

 ally found breeding in small numbers. Noth- 

 ing is known about fluctuations in its num- 

 bers in Alaska. 



This species is common in both British 

 Columbia and Washington; nesting sites are 

 of the same type as those in Alaska except in 

 the San Juan Islands, where 200-300 birds 

 nest on cliff faces composed of glacial de- 

 posits. Here, there is frequent nest loss due to 

 slippage off the cliff face; this loss is espe- 

 cially severe on Smith and Protection islands. 

 There do not appear to be any changes in the 

 distribution of pelagic cormorants, but an 

 accurate assessment of abundance is impos- 

 sible from the data currently available. 



Glaucous-winged Gull (Larus glaucescens) 



The glaucous-winged gull is the character- 

 istic gull of southeastern Alaska and British 

 Columbia. In Washington, it is the dominant 

 gull in the San Juan Island area but inter- 

 breeds with the western gull on the Washing- 

 ton outer coast from Tatoosh to Copalis 

 Beach (Scott 1971). In Alaska, it is widely dis- 

 tributed and locally abundant on Forrester Is- 

 land, St. Lazaria, and throughout Glacier Bay 

 (S. Patten, personal communication). The 

 biology of this species has been extensively 

 studied in the southern part of its range, espe- 

 cially by Vermeer (1963) and James- Veitch 

 and Booth (1954). The only study of the breed- 



ing biology of this species in southeastern 

 Alaska is by Patten (1974) for Glacier Bay. 

 Glaucous-winged gulls are apparently increas- 

 ing in British Columbia (R. W. Campbell, un- 

 published data) and in Washington (T. R. 

 Wahl, personal communication). This increase 

 is undoubtedly a result of the proximity of 

 breeding colonies to garbage dumps and com- 

 mercial fishing fleets in both Canada and the 

 United States. Little is known about changes 

 in populations of gulls in southeastern 

 Alaska. 



Western Gull (Larus occidentalis) 



The western gull is the common breeding 

 gull of the Washington outer coast; however, 

 there is increased interbreeding with glau- 

 cous-winged gulls northward from Destruc- 

 tion Island to Tatoosh Island. The percentage 

 of glaucous-winged gulls steadily increases 

 until Vancouver Island and the Strait of Juan 

 de Fuca, where western gulls are rare. Popula- 

 tion estimates of gulls on the outer coast of 

 Washington are derived primarily from aerial 

 flights. This makes identification of gulls dif- 

 ficult, and in view of the amount of interbreed- 

 ing, it is probably impossible to classify many 

 of the breeding gulls as to species. Western 

 gulls appear to be increasing in the Grays 

 Harbor area (G. D. Alcorn, personal com- 

 munication). 



Herring Gull (Larus argentatus) 



The herring gull is typically found in inland 

 Alaska but can be found uncommonly along 

 the coast of southeastern Alaska, where it 

 often forms mixed colonies with glaucous- 

 winged gulls. These two species apparently 

 hybridize where they are sympatric (William- 

 son and Peyton 1963; Patten and Weisbrod 

 1974; Patten 1974). 



Black-legged Kittiwake (Rissa tridactyla) 



The black-legged kittiwake is found only in 

 the northern portions of southeastern Alaska. 

 It apparently is a common breeding bird in 

 Glacier Bay National Monument (S. M. 

 Patten, Jr., personal communication). No 

 population estimates are available for this 

 species other than that it is locally abundant. 



