November, 1919] 



The Canadian Field-Naturalist 

 A NEW CLIFF SWALLOW FROM CANADA. 



95 



By Harry C. Oberholser. 



The form of Peirochclidon albifrons^ inhabiting 

 most of western Canada proves to be subspecifically 

 distinct from the typical race. It may be described 

 as follows: 

 Petrochelidon ALBIFRONS HYPOPOLIA, subsp. nov. 



Chars, subsp. — Similar to Petrochelidon albi- 

 frons albifrons from eastern United States and Col- 

 orado, but larger; frontal band paler, more whitish; 

 breast more grayish (less ochraceous). 



Description. — Type, adult male. No. 195055, U. 

 S. Nat. Mus., Biological Survey collection; Fort 

 Norman, Mackenzie, June 11, 1904; E. A. Preble, 

 original number, 1830. Forehead creamy white; 

 crown metallic blue black; hind neck brownish 

 gray; back and scapulars, like crown, but streaked 

 with brownish gray and whitish; rump cinnamon; 

 upper tail-coverts light fuscous, the tips of the feath- 

 ers whitish; tail fuscous; wings fuscous black, with 

 a slight metallic bluish or greenish sheen, the inner 

 edges of the primaries and secondaries paler and 

 on terminal portion narrowly edged with brownish 

 white, the outer webs of the inner secondaries and 

 of the tertials margined with the same, and the 

 greater wing-coverts slightly tipped with paler 

 brown; lores and narial bristles, brownish black; 

 sides of the head below the eyes, together with the 

 upper throat, between chestnut and bay; chin and 

 centre of the lower throat, black ; sides of neck 

 light brownish gray; breast, sides, and flanks, light 

 brownish gray, the centre of the breast washed with 

 pale cinnamon ; remainder of the lower parts dull 

 white, the crissum washed with chestnut; lining of 

 wing light brownish gray; edge of wing barred with 

 dull light cinnamon and brownish gray. 



Measurements. — Male:- wing, 110-115 (average, 

 112.1) mm.; tail, 49-52 (50.7); exposed culmen, 

 6-8 (7.2); tarsus. 11-13 (12.3); middle toe 

 without claw, 10.5-12 (11.3). 



Female: wing, 108-111.5 (average, 110.2) mm.; 

 tail. 49.5-51.5 (50.7); exposed culmen, 6-8-7.2 

 (7.0); tarsus, 13; middle toe without claw, 12- 



12.5 (12.3). 



Geographic distribution. — Breeds in northwestern 

 North America, north to Mackenzie and central 

 Alaska; west to central British Columbia; south to 

 Montana; and east to Alberta and Mackenzie. 

 Migrates through Wyoming and California. Win- 

 ters probably in South America. 



1 Kor tlie chaiiKf of name l"i-oni IV'lroclu'lidon 

 lunifrons to to I'etroclu'lidoii aIl)ifrons, cf. Uhoades, 

 AliU, XXIX, No. 2, April. 1!I1L'. i)|). l!i:<-l!t.'->. 



i-'Fivc sjU'ciiiKMis, fnmi Alaska. Marlscir/io. ami 



Montana. 



This is the largest of the races of Petrochelidon 

 albifrons, and differs from Petrochelidon albifrons 

 tachina still more than from the typical Petrocheli- 

 don albifrons albifrons. The difference in measure- 

 ments between Petrochelidon albifrons albifrons 

 and our new Canadian race may be seen by com- 

 parison of the figures above given for the latter with 

 the followmg dimensions of Petrochelidon albifrons 

 albifrons taken from Colorado, Wyoming, and east- 

 ern United States birds. 



Male:' wing, 105-112 (average, 107.6) m.ni.; 

 tail, 47-51 (49.9); exposed culmen, 7-8 (7.2); 

 tarsus, 12-13 (12.6); middle toe without claw, 11- 

 12 (11.8). 



Female:^ wing, 102-109 (average, 107.2) mm.; 

 tail, 47-51 (48.9); exposed culmen, 7-8 (7.4); 

 tarsus, 11.5-13 (12.5); middle toe without claw, 

 11-13 (11.9). 



Breeding birds from Dickey in southern Idaho, 

 the Snake River in eastern Washington, and from 

 Ashcroft in central southern British Columbia, are 

 apparently referable to Petrochelidon albifrons 

 albifrons. Specimens from Greybull and Saratoga, 

 Wyoming, are in size about half-way between 

 Petrochelidon albifrons albifrons and Petrochelidon 

 albifrons hypopolia, but in color they are decidedly 

 nearer the former, and are here included under that 

 race. A single specimen from Pembina, North 

 Dakota, indicates that the bird from at least the 

 northeastern part of North Dakota is the eastern 

 form. The present new race migrates through the 

 western United States, as spring examples from 

 Wyoming and southern California indicate. 



All the specimens of Petrochelidon albifrons 

 hypopolia examined are included in the following 

 list: 



Alaska. Nulato (May 24, 1867); St. Paul 

 Island (about June 10, 1918). 



Arizona. Tucson (April 18, 1918). 



Mackenzie. Fort Resolution (June 23, — ) ; 

 Fort Good Hope (June 20, 1904); Fort Norman 

 (June 11, 12. and 14, 1904). 



California. Laguna Station, San Diego County 

 (May 4. 1894).- 



Montana. Milk River at 49 north latitude (July 

 25, 1874); Johnson Lake (June 3. 1910); Fort 

 Benton. 



Wxfoming. Ten Sleep (May 31, 1910). 



•tSeven .specimens. 

 ■il'-Iovon srecln-.ciis. 



