94 Wyoming Experiment Station. 



scarlet nuchal crescent, where coincidently we find the char- 

 acteristics golden-yellow on the wing and tail passing through 

 an intermediate orange into the red of mexicanus, a change 

 which accompanied with another affecting the peculiar lilac- 

 brown of the throat and olive-green of the back, which be- 

 come respectively merged into ashen and purplish-gray. 



"If there ever was a case of hybridization to an unlim- 

 ited extent, resulting in fertile offspring, that algain and again 

 interbred, this would appear to be one ; and it has been so ac- 

 cepted by the majority of ornithologists without hesitation. 

 But we may well pause before committing ourselves to an 

 hypothesis of hybridization, on such an immense scale. In the 

 light of late researches upon the question of climatic variation 

 according to inflexible and infallible laws, most of the lesser 

 instances of supposed hybridity have seemed less weighty. 

 The present may be considered a test case — ^the strongest ar- 

 gument of those who, maintain hybridity." 



413. Colaptes cafer collaris (Vigors.). 

 Red-shafted Flicker. 



Summer resident and common in wooded districts up to 

 9,000 feet. Cook. in Birds of Colorado, p. 85, says that this 

 bird "breeds from the plains up to 12,000 and is almost as 

 common at 11,000 feet as on the plains." Since timberline is 

 about 10,000 feet in this section of the Rocky mountains I 

 can not understand how this species breeds above the limit 

 of trees. In Wyoming and Colorado I visit the mountain 

 country a great deal ; but have never found these birds above 

 10,000 feet. On the other hand I have often seen them upon 

 the desert country feeding in the sagebrush and greasewood 

 and many miles from a tree of any size. Records are abundant 

 from all parts of the state; but this species is more abund- 

 ant west of the Laramie mountains than east of them. Dr. 

 Cooper took a specimen at Fort Laramie in 1857 ; Drexel at 

 Fort Bridger in 1858; Grinnell found them abundant in Yel- 



