170 NORTH AMERICAN FAUNA 61, FISH AND WILDLIFE SERVICE 



On Hazen Point, June 13, 1925, I watched large flocks of gray, 

 immature gulls resting 400 yards inland from shore during ebb 

 tide. This area was covered with numerous oval pellets com- 

 posed of crab fragments. I also found clam shells, which were 

 partly overgrown with vegetation. Obviously, this was a favorite, 

 perhaps an ancestral, resting area, where nonbreeding glaucous- 

 winged gulls had rested and digested food gleaned from the last 

 ebb tide. 



Ecological Relations 



It is clear that the clever, adaptable glaucous-winged gull 

 finds its living in a great variety of ways, effectively filling the 

 ecological niche in which it happens to find itself. What is the 

 effect on its environment? 



The gull is a scavenger, and the effect of its food habits may 

 be somewhat beneficial to man. Gleanings from the beach, which 

 include crabs, clams, sea urchins and other "shellfish" probably 

 do not upset any balance and, so far as we know, have no bearing 

 on human interests in the area considered here. 



As for depredations in murre and eider colonies, we did not 

 work out the ecological problem in any systematic way, yet 

 certain observations may be significant. Perhaps nowhere are 

 depredations more severe than in a murre colony. However, on 

 Bogoslof Island, where such gull depredations on eggs and young 

 have continued for a long time, the murres were present in great 

 numbers and were utilizing all the available nesting sites. The 

 same situation seemed to prevail on other islands. For more 

 detailed consideration of this matter, the reader is referred to 

 the discussion of the murre. 



Likewise, the Pacific eider, which also is preyed upon by these 

 gulls, appears able to produce a satisfactory increase in population 

 by the end of the summer. It should be remembered that this 

 eider is not preyed upon by man to any appreciable extent, except 

 for the robbing of nests for fresh eggs in a few localities. View- 

 ing the situation as a whole, it appears that, at least in the 

 Alaska Peninsula-Aleutian Islands district, the Pacific eider and 

 the murre, as well as other species, survive in satisfactory num- 

 bers in spite of the gulls. 



The glaucous-winged gull is believed to feed on salmon eggs 

 and to prey upon the spawning salmon in shallow streams. This 

 question would require special study, with attention given to the 

 breeding habits and ecological requirements of salmon and the 

 percentage of loss occasioned by the gulls. Naturally, such de- 



