NORTH AMERICAN GULLS AND THEIR ALLIES. 49 



- [MEW GULL. Larus canus Linnaeus. 



The mew gull is a species of the Eastern Hemisphere, having there a wide range from 

 northern Europe and Asia to the Mediterranean, the Nile, and the Persian Gulf. On 

 the Pacific coast it occurs from the northern coast of the Sea of Okhotsk, Kamchatka, 

 and Bering Island, to Japan and China. 



The only sure record for North America is that of a specimen taken by Dr. Coues at 

 Henley Harbor, Labrador, August 21, 1860. This specimen found its way to the 

 British Museum. 



The mew gull has been erroneously recorded several times on the coast of California. 

 One recorded November 30, 1905, at Pacific Beach, was a young ring-billed gull, and 

 one reported April 14, 1907, from Alamitos Bay proved to be the Pacific kittiwake. 

 Early records of Loomis and late records of Beck, from Monterey Bay, are referable 

 to the short-billed gull.] 



HEERMANN'S GULL. Larus hccrmanni Cassin. 



Range. — Pacific coast from British Columbia to Mexico. 



Heermann's gull is the only member of the group that regularly 

 migrates in summer to the north of its breeding grounds and is com- 

 mon in the United States at that season, though not as yet known 

 to breed north of Mexico. Up to date only a few nesting places are 

 known. In April, 1875, Dr. Streets found an immense colony pre- 

 paring to breed on Isla Raza, on the west side of the Gulf of California 

 near latitude 29°. Though eggs had not yet been laid, the birds 

 were mating, and the presence of many thousands of tons of guano 

 bore witness to the fact that the island had been used as a breeding 

 place for untold generations. 



The eggs of Heermann's gull have been among the desiderata of 

 collectors for many years, and it is noteworthy that they should at 

 last have been found in the same month at widely separated locali- 

 ties by two expeditions sent out principally for this purpose. W. W. 

 Brown, jr., collecting for J. E. Thayer, found a colony, March 28, 1909, 

 on Idlefonso Island, near the west coast of the Gulf of California, 

 latitude 26° 30'. The first eggs from a colony whose nests were 

 estimated as at least 2,500 were not obtained until April 2. Nine 

 days later eggs were found by Osburn and Lamb on Las Marietas 

 Islands, off the coast of Jalisco, latitude 20° 30'. The eggs at the 

 more southern colony, which contained less than a hundred pairs, 

 had been laid so much earlier that some hatched April 14. 



The original discoverer of this species, Dr. A. L. Heermann, said that 

 it bred on Los Coronados Islands, Lower California, near San Diego, 

 but this statement was probably not based on the finding of the eggs, 

 but on the presence of the bird on the near-by coast during the 

 breeding season. Later observers have failed to find the species 

 nesting on these islands, or, indeed, anywhere along the whole west- 

 ern coast of Lower California, though it has been reported breeding 



