50 



BULLETIN 292, U. S. DEPARTMENT OF AGRICULTURE. 



at Magdalena Bay (Bryant), on the Tres Marias (Bailey), and at 

 Mazatlan (Lawrence). 



The species is present the whole year on the coast of Lower Cali- 

 fornia and western Mexico from the United States boundary to 

 Tepic, a distance of over a thousand miles, and it is not probable that 

 all these untold thousands of birds gather for nesting purposes on 

 the few acres of the two islands where their eggs have been obtained. 



As soon as the young birds are strong of wing both old and young 

 begin to work their way northward. On the southern coast of Cali- 



Fig. 24. — Heermann's gull (Larus heermanni). 



fornia, where only a few birds are present after the middle of March, 

 the numbers begin to increase the last week in May and early in 

 June (Willett). The first northward migrant reached Eureka, Cal., 

 June 1, 1889 (Palmer), and William Head, Vancouver Island, British 

 Columbia, June 28, 1904 (Kermode). The species is an abundant 

 summer migrant along the whole coast and has been taken north to 

 the northern end of Vancouver Island (Saunders). 



Its stay in this northern part of the range is not prolonged. In 

 1894, by the end of July flocks were beginning to pass southward at 

 Monterey Bay, Cal. (Loomis). Though common during July and 

 August at the southern end of Vancouver Island (Kermode), by 



