THE BIRDS OF BOULDER COUNTY 233 



464. Empidonax difficilis — Western Flycatcher. 



Common summer resident in mountains. Have seen it on the edge of the plains only 

 in migration. Nine nests in Gale collection were taken at from 8,500 to, 10,000 feet and 

 three of them were from mine shafts or tunnels, all in June and early July. 

 466. Empidonax traillii — Traill Flycatcher. 



Common summer resident of plains and perhaps lower mountains. Five nests in 

 Gale collection, all from the plains, and three contained a cowbird egg each. Felger has 

 one bird taken by Gale at 5.500 feet, July 3, 1890. 

 [467. Empidonax minimus — Least Flycatcher. 



Gale's notes mention one nest of this species, leaving it uncertain as to whether it was 

 in the foothills or on the plains. Identity too doubtful for retention of record.] 



468. Empidonax hammondi — Hammond Flycatcher. 



Summer resident of mountains. Two nests were taken by Gale at 10,000 feet (Ben- 

 dire). 



469. Empidonax wrightii — Wright Flycatcher. 



Common on plains, breeding in mountains, where Gale found it nesting up to 10,000 

 feet. 

 474c. Otocoris alpestris leucolaema — Desert Horned Lark. 



Abundant resident on dry plains and in the mountains. Gale found it nesting on the 

 open slopes above timber-line and on the dry plains, but at no intermediate point. In the 

 severe winter of 1898-9 many thousands appeared on the streets of Boulder and were 

 fed by the citizens. The nests, being on the ground, are often destroyed by heavy spring 

 snows, whereupon they re-nest. I assign all our horned lark records to this species. 

 475. Pica pica hudsonia — American Magpie. 



Common resident of plains and up to about 8,000 feet, less common to timberline. 

 478b. Cyanocitta stelleri diademata — Long-crested Jay. 



Common resident of foothills and]mountains, breeding mostly at from 7,000 to 9,000 

 feet. Performs a regular spring and autumn vertical migration, often accentuated in the 

 autumn by severe weather. Occasional in winter some distance out on the plains. 

 480. Aphelocoma woodhouseii — Woodhouse Jay. 



Have seen only the specimen in the University cabinets collected by Bragg in the 

 foothills near Boulder in 1904. Felger has one taken by Gale on the St Vrain, October 

 31, 1887. 

 484a. Perisoreus canadensis capitalis — Rocky Mountain Jay. 



Resident of the higher mountains, mostly above 8,000 feet. Have seen a few in 

 Boulder twice during severe winter weather. Gale found young birds twice at 10,000 

 feet and once at 11,000, but never found nest and eggs. 



487. Corvus cryptoleucus — White-necked Raven. 



Noted at Boulder in 1894 by R. A. Campbell (Cooke). Not since recorded. 



488. Corvus brachyrhynchos — American Crow. 



Noted on plains by Gale. Seldom seen now. Blanchard reported a flock in Boulder 

 Canyon, December 1, 1906, and Markman reported a flock, possibly the same one, on the 

 foothills at Boulder six days later. Rockwell noted the species near Boulder, March 26, 

 1904. 



