LIFE HISTOBIES OF NORTH AMERICAN GULLS AND TERNS. 123 



habits is very meager. Until the limits of its breeding range are 

 well known, and until a large series of specimens have been collected 

 in that region, the correct status of the species can not be determined. 



If not identical with the herring gull it is certainly closely related 

 to it, and its habits, so far as we know, are similar. It is therefore 

 fair to assume that its life history closely resembles that of the com- 

 moner species, due allowance being made for any differences in en- 

 vironment. 



Nesting.-^- There are three sets of eggs of this species in the author's 

 collection, all of which were taken by Mr. Johan Koren at the mouth 

 of the Kiver Kolyma in northeastern Siberia, where he found it an 

 abundant species along the Arctic coast. Two of these nests were 

 photographed for illustration in this work. The first nest was 

 located on a shelf on a steep bluff 200 feet high, on the bank of the 

 river, where glaucous gulls were also nesting. It contained three 

 eggs, which were nearly ready to hatch on July 10. Another set of 

 three eggs, incubated about 15 days, was taken on July 2. A large 

 nest of moss and straws had been built over the root of a stranded 

 tree trunk, which drifted onto a low, grass-grown islet of the delta. 

 The third set was taken on July 6 and consisted of two eggs, incu- 

 bated seven days. The nest was made of moss and straws in a bog 

 on a low island of the delta ; a colony of six pairs of Vega gulls were 

 breeding on the island. 



Eggs. — The above three sets of eggs are so different in coloring 

 that they are worth describing, as representing the usual variations 

 in eggs of this species. In the first set the ground color is " deep 

 olive buff" ; the eggs are sparingly spotted over the entire surface 

 with rather small spots of " fuscous," " Vandyke brown," " Dresden 

 bfown," and " ehestnut brown," over underlying spots and blotches 

 varying from " pale drab gray " to " hair brown." The second set 

 is paler, " olive buff," one egg having a decidedly greenish tinge ; this 

 latter egg is heavily and fantastically blotched with dark shades of 

 " chestnut brown " and "Vandyke brown." The third set represents 

 the brownish type ; the ground color carries from dull " snuff brown " 

 to dull "tawny olive"; the three eggs are all heavily spotted, chiefly 

 about the larger ends, with confluent spots of " hair brown," " drab," 

 " warm sepia," and dark " Vandyke brown." All of these eggs could 

 be closely matched with similar types of herring gull's eggs, which 

 they resemble in general appearance. The measurements of 30 

 eggs, in various collections, average 70.4 by 49.5 millimeters; the 

 eggs showing the four extremes measure 77.5 by 50.5, 75.5 by 53.1 

 and 65 by 47.5 millimeters. 



Plumages.— The downy is similar to that of the herring gull, but 

 what specimens I have seen average darker gray in color, less buffy, 



