LIFE HISTORIES OF NORTH AMERICAN GULLS AND TERNS. 153 



water " until it was supposed to be far enough from its parasite to venture 

 s\valIowing_ it, but as the huge bill was tipped up and opened the gull plunged 

 forward and thrust its entire head and neck into the pouch ; the pelican, some- 

 what quicker than niost of its kind, closed down with a snap and caught the 

 intruder, which in turn had caught the lish ; neither would yield any advan- 

 tages gained, and for perhaps half a minute the pelican towed the gull about by 

 the head, amid most violent protest from a hundred or more gulls assembled, 

 while other pelicans sat like solemn judges, perhaps offering to arbitrate the 

 question. At last a more violent twist than usual on the part of the gull freed 

 him from limbo, minus a few feathers, but in no manner daunted, for a moment 

 later it was following closely in the wake of the same pelican, waiting for it to 

 plunge for another fish, and I never did learn which really swallowed the one in 

 controversy. 



Dr. E. W. Nelson (1899) observed that "these gulls are bold and 

 noisy aggressors when they wish to take advantage of the gannets, 

 and about the breeding places of the latter they feed largely at the 

 public expense." One that he shot on Isabel Island, off the west 

 coast of Mexico, had in company with its mate " harried a blue- 

 footed gannet into disgorging a number of small fish upon a rock 

 at the edge of the water, and was picking up the spoils by a series of 

 little downward swoops and hoverings." Mr. Harold H, Bailey 

 (1906) in the same region, noted similar behavior toward the boobies. 

 He also mentions the following incident: 



One day while sitting on a rock in front of camp at White Rock waiting for 

 lunch, I saw one of a pair of great rufous-bellied kingfishers fishing from a 

 rock about 20 feet farther on. As it returned to its perch from one of its little 

 plunges a Heermaun's gull swooped down and tried to get its food before it 

 could be swallowed. The kingfisher dove to the water and at each descent of 

 the gull, dove below, these tactics being kept up until the gull got disgusted and 

 left. 



Winter. — At the close of the breeding season the Heermami's gulls 

 migrate northward along the coast of California and as far north as 

 British Columbia. They have been seen flying north along the coast 

 of Washington as early as July. Adults become abundant on the 

 California coast in July and young birds in August. They are com- 

 mon all winter on the coast of southern California, both adults and 

 young, until the adults migrate south again in the spring to breed. 



DISTKTBTTTION. 



Breeding range. — Pacific coast of Mexico. Known to breed in the 

 Gulf of California (Isla Raza and Ildefonso Island), Lower Cali- 

 fornia (Magdalena Bay), on the Tres Marias Islands, and at 

 Mazatlan. 



Winter range. — Northward in summer along the Pacific coast to 

 northern Washington (Puget Sound), and occasionally to northern 

 Vancouver Island. Southward along the Central American coast to 

 Guatemala (Chiapam and San Jose). 



