NORTH AMERICAN GULLS AND THEIR ALLIES. 59 



on the coast of British Columbia (Kermode). To this same class 

 should probably be referred the birds seen at the north end of Lake 

 Winnipeg, June 15-17, 1900 (Preble), July 7-9, 1900, in southern 

 Keewatin (Preble), and the late June birds of the Bay of Fundy 

 (Brewer). Audubon notes that individuals found to be abundant 

 about the Bay of Fundy in May were birds one year old that on dis- 

 section showed they were not to breed that year. 



Winter range. — Bonaparte's gull winters regularly and commonly 

 on the coast from Florida to South Carolina, less commonly to Long 

 Island, and stragglers have occurred at this season north to Maine. 

 It winters on the Gulf coast of the United States and on the Pacific 

 coast north at least to southern Washington. On the coast of Los 

 Angeles County, Cal., it winters commonly, and less commonly to 

 San Quintin, Lower California, January 12, 1907 (Thayer); Mag- 

 dalena Island, Lower California, December 5, 1905 (Nelson and Gold- 

 man) ; Mazatlan, Sinaloa, December, 1896 (Loomis) ; and to La Barca, 

 Jalisco (specimen identified at the Biological Survey). It ranges in 

 Florida south to Lemon City (Brown) , was noted at Progreso, Yucatan, 

 in late January (Cole), and winters at the mouth of the Colorado 

 River (Rhoads). 



Migration range. — Breeding in the interior on fresh water, Bona- 

 parte's gull seeks salt water as soon as its family cares are concluded. 

 Although the principal breeding range is in the northwestern part of 

 the American Continent, many more than half of the gulls go east- 

 ward in their migration to spend the winter on the Atlantic coast. 

 The line of flight corresponds in general with the northern limit of 

 tree growth, reaching the coast of Hudson Bay in the vicinity of Cape 

 Churchill, and thence passing around its southern end to the Gulf of 

 St. Lawrence ; a few individuals occur along the Labrador coast at the 

 Strait of Belle Isle and as far north as Hamilton Inlet (Bigelow). 

 Another numerous group choose a route a little to the southward by 

 way of Lake Winnipeg and the Great Lakes to the Atlantic coast. 



Small numbers go south in fall through the Mississippi Valley to 

 winter on the Gulf coast, but only a few choose this route, for Bona- 

 parte's gull is a bird of lakes rather than rivers, and there are few 

 congenial stopping places in the southern half of the Mississippi Valley. 



The small contingent electing the Pacific coast for their winter 

 home go directly south, crossing the main divide of the Rocky Moun- 

 tains to the coast of southern Alaska, whence they follow down the 

 coast to the .winter home. A few seem to wander up the valley of 

 Peace River and cross southern British Columbia to the coast. 



The same routes seem to be retraced in spring, except that the 

 Atlantic coast birds at this season probably do not go northeast of 

 the western part of the Gulf of St. Lawrenee. 



