1 66 BiRTWELL, Description of a new Chickadee. \ h^^\ 



In brief, while the migrants are of the normal colors as well as 

 those birds wintering in the cedar covered foothills about twelve 

 miles from the valley, and those breeding among the mountain 

 parks of the Pecos River Forest Reserve, the winter residents of 

 the valley are heavily melanistic, and no ordinary chickadee appears 

 to occupy the valley in the cold months with them. In the early 

 spring the melanistic birds vanish and are not observed again 

 until the next cold weather. These statements are also supported 

 by the results of twenty-one years observations of Mr. W. H. Cobb 

 of Albuquerque, about that city, which collectively considered, 

 oppose the possible suggestion that the melanistic birds are but 

 occasional examples of melanism. 



Examinations of a large series of specimens show the strange 

 birds to be peculiar to the Rio Grande valley alone, in the vicinity 

 of Albuquerque. Sixty specimens kindly loaned from the National 

 Museum exhibit no examples or even transition forms and these 

 embrace specimens of various seasons from California, Nevada, 

 Oregon, Utah, Colorado, Arizona and New Mexico. The nearest 

 approach to the supposed new form is from Palmer Lake, Colo- 

 rado, but the resemblance is slight. 



As shown by these specimens and by others, as well as many 

 collected personally, the winter form of the valley deserves at 

 least subspecific recognition. Specific rank is possible, but the 

 birds belong to the gambeli series and bear the same relation to 

 Paras gambe/i as Bueto borealis caliirus bears to boreaUs. 



It is proposed to describe the new form as follows : 



Parus gambeli thayeri, subsp. nov. 



Tj'pe, No. 226, author's collection, adult, sex.', Albuquerque, N. M., Dec. 

 27, 1900. 



Habitat (so far as known) : Vallej of the Rio Grande, near Albuquer- 

 que, in Avinter. 



Subsp. char. — Similar to Parus g'afiibeli, but whole body markings, 

 including the white of head and underparts, the black head areas, the ashy 

 shade of the dorsum and the wings and tail, overcast with dull, heavy 

 melanistic effects. In the type specimen the underparts ai-e blackish slate 

 slightly tinged with tawny on the sides, and this intensity represents the 

 average example as observed by me. Bill and feet as in gambeli, black. 



