LIFE HISTOBIES OF NORTH AMERICAN GULLS AND TERNS. 91 



breeding range in the bird reservations on the coast of Washington, 

 where it mingles with the glaucous- winged gull at the southern limit 

 of the latter's breeding range. 



Nesting. — Dawson (1909) says that the northernmost colony of 

 unmixed occidentalis on the Washington coast is on Willoughby 

 Rock, off Cape Elizabeth; "but scattered pairs occur, along with 

 glaucous wings, as far up as Carroll Islet." He says of its nesting 

 habits : 



Nesting is undertaken in May, and by the 20th of that month, or by June 10 

 at the latest, the complement of three eggs is laid. Nests are composed almost 

 exclusively of dried grasses plucked by the birds, roots and all ; and these be- 

 come quite substantial structures if the grass is convenient. Ledges, crannies, 

 grassy hill sides, and the exposed summits of the rocks are alike utilized for 

 nesting sites; while occasionally a bird ventures down so close to the tide line 

 as to lose her eggs in time of storm. Chicks are brought oft by the third week 

 in June or by the 1st of July, according to season, if unmolested. If the first 

 set is removed, however, the birds will prepare a second, consisting almost in- 

 variably of two eggs, and these are deposited as likely as not in the same nest 

 as the former set. Deposition occurs at intervals of two or three days. 



On the Three Arch Rocks, Oregon, Mr. W. L. Finley (1905) de- 

 scribes the nesting of this species as follows : 



The gull picks out a comfortable spot and builds a respectable nest, and that 

 is about the only creditable thing he does on the rock. The grass-covered roof 

 of the island is his favorite nesting place, although many select the niches in 

 the bare rock on the face of the cliff. The gull's eggs lie right out in the open 

 and never seem to be bothered by other birds; they themselves do not ravage 

 the homes of their own kindred. The eggs are of dull earthy and chocolate- 

 brown tints, with darker blotches, matching their surroundings so perfectly 

 that we had to be constantly on the lookout to keep from stepping on them. 

 When the eggs were hatched we found the nestlings were protected by equally 

 deceptive clothes of a mottled gray color. 



The best known breeding grounds of the species are on the Faral- 

 lon Islands, which have been well described by several writers. 

 According to Mr. W. Otto Emerson, who sent some original notes on 

 the subject to Major Bendire, the gulls begin building or repairing 

 their old nests about May 1, and the nesting season is prolonged 

 through May and June. The nests are built wholly of dry Farallon 

 weed, Baeria maritima, the old nests being used year after year. 

 After being robbed the birds soon begin laying again, and he noted, 

 by watching a certain nest, that an egg was laid every other day. 



Mr. Milton S. Ray (1904) has given us the following good account 

 of the Farallon colonies : 



While this bird builds in colonies, so to speak, they are not like those of the 

 cormorant or murre. There is always fighting room between the nests, and 

 only the aggregations near Shell Beach, Indian Head, and at Guano Slope on 

 West End, and about Tower Point on East End, could well deserve this term. 



