286 BULLETIN 17 9, UNITED STATES NATIONAL MUSEUM 



Its habitat is different from those of the other small western fly- 

 catchers, and its notes are quite distinctive. 



Enemies. — Dr. Friedmann (1929) says that "this species seems to 

 be a rather uncommon host of the small, southwestern race of the 

 Cowbird — the subspecies ohscurusy 



DISTRIBUTION 



Range. — Western North America, south to northwestern South 

 America. 



Breeding range. — The western wood pewee breeds north to central 

 Alaska (Fairbanks and near Circle) ; southern Yukon (Little Salmon 

 River) ; southwestern Mackenzie (Fort Simpson, Fort Providence, 

 and Fort Smith) ; northeastern Alberta (Athabaska delta) ; central 

 Saskatchewan (Big River and Cumberland House) ; and southeastern 

 Manitoba (Winnipeg). East to eastern Manitoba (Winnipeg and 

 Treesbank) ; northeastern North Dakota (Grafton) ; southwestern 

 South Dakota (Elm Mountains and Hot Springs) ; western Nebraska 

 (Henry) ; central Colorado (Fort Collins, Denver, and Beulah) ; eastern 

 New Mexico (Montoya and Roswell) ; western Texas (Fort Hancock) ; 

 Veracruz (Perote and Presidio) ; Guatemala (Progreso) ; and Costa 

 Rica (La Hondura and Boruca). South to Costa Rica (Boruca) ; 

 Chiapas (Tonala) ; Guerrero (Chilpancingo) ; and southern Baja 

 California (San Jose de Rancho and La Laguna Mountains). The 

 western limit of the breeding range extends northward along the 

 Pacific coast from Baja California (La Laguna Mountains and the 

 San Pedro Martir Mountains) to Alaska (Chickamin River and 

 Fairbanks) . 



Winter range. — The winter range of this species is imperfectly 

 known, but at this season it appears to be concentrated in Central 

 America and northwestern South America. It has been recorded 

 north to Oaxaca (Topanatepic) and south to Bolivia (Nairapi) and 

 Peru (La Gloria and La Merced). 



As outlined the range includes three currently recognized subspe- 

 cies. The typical form {Myiochanes richardsoni richardsoni) is found 

 in summer from Alaska and Mackenzie south to northern Mexico and 

 in winter south to Ecuador, Bolivia, and Peru ; the large-billed wood 

 pewee {M. r. peninsulae) breeds in southern Baja California and is 

 found in winter on the mainland of Mexico and south to Guatemala ; 

 the third form, the Mexican wood pewee {M. r. sordidulus), breeds 

 in the highlands of southern Mexico and winters south to Peru. 



Spring migration. — Early dates of spring arrival are : Texas — San 

 Antonio, April 15. New Mexico — State College, April 25. Colo- 

 rado — Boulder, May 3. Wyoming — Cheyenne, May 13. Montana — 

 Columbia Falls, May 20. Saskatchewan — Eastend, May 20. Mani- 



