270 BULLETIN 17 6, UNITED STATES NATIONAL MUSEUM 



DISTRIBUTION 



Range. — Western North America; closely related nonmigratory 

 races are found in southern Central America and in the West Indies. 



Breeding range. — The breeding range of the black swift extends 

 north to southeastern Alaska (Portage Cove) ; and northwestern 

 British Columbia (Telegraph Creek). East to British Columbia 

 (Telegraph Creek, Hazelton, and 158-mile House) ; southwestern 

 Alberta (Banff) ; probably western Montana (Libby, Glacier National 

 Park, and Stryker) ; and southwestern Colorado (Howardsville). 

 South to southwestern Colorado (Howardsville) ; and southern Cali- 

 fornia (Cerro Gordo, Sequoia National Park, and Santa Cruz). West 

 to California (Santa Cruz, Berry Creek, and Yosemite Valley) ; 

 western Washington (Seattle and Bellingham) ; British Columbia 

 (Chilliwack and Okanagan Landing) ; and southeastern Alaska 

 (Boca de Quadra and Portage Cove). 



Winter range. — Unknown. Despite repeated statements that this 

 species spends the winter season in southern Mexico, an examination 

 of the available data fails to substantiate the assertion, the dates of 

 observation or collection being entirely within the seasons of migra- 

 tion. Accordingly, while it is possible that these birds do winter 

 with the resident form in southern Central America, factual evidence 

 is at present lacking. 



Spring migration. — Early dates of spring arrival are: Baja Cali- 

 fornia — San Telmo, April 30. California — Hay wards, April 19; 

 Grapevine, April 24; Yosemite Valley, May 11. Washington — Seat- 

 tle, May 16; Simialmoo, May 27. British Columbia — Chilliwack, 

 May 8 ; Courtenay, May 15 ; Lulu Island, May 25 ; Alberni, June 9. 



Fall migration. — Late dates of fall departure are : Alaska — Sergief 

 Island, September 7. British Columbia — Hazelton, August 29; 

 Errington, September 20; Okanagan Landing, September 26; Cour- 

 tenay, September 29. Washington — Bellingham, September 1; 

 Seattle, October 7. Oregon — ^Albany, September 22. California — 

 Santa Cruz County, September 13; Hay wards, October 1. 



Casual records. — Among the records of occurrence of the black 

 swift outside the range as above outlined are the following cases: 

 New Mexico, reported from Willis in September 1883 and noted at 

 Lake Burford, on September 28, 1904; Arizona, seen at Flagstaff on 

 August 18, 1920; eastern Colorado, two seen on July 8 and three on 

 July 10, 1910, in Estes Park, several seen near Trinidad, July 8-14, 

 1892, while a specimen in the collection of George B. Sennett was 

 labeled as taken at Denver on June 26, 1884; and Idaho, taken or 

 observed on the Malade River on August 13, 1834. A specimen came 



