1914] Grinnell: Mammals and Birds of the Colorado Valley 213 



noted regularly down along the river until the first week in April. 

 when it became scarce; the last one noted was secured April 18, on 

 the California side eight miles east of Picacho, this being the only 

 individual seen at this point. The other localities of capture, lying 

 between the two above-named, are as follows : on the California side : 

 opposite The Needles, Chemehuevis Valley, Riverside Mountain, Blythe, 

 opposite Cibola, twenty miles north of Picacho; on the Arizona side: 

 Mellen, foot of The Needles, Ehrenberg, ten miles south of Cibola. 

 In all these places the kinglets were seldom seen outside of the willow 

 association. 



The series of twenty-four specimens obtained, nos. 13946-13969, 

 is uniform in its exhibition of the characters assigned to Begulus cah n- 

 dula cineraceus (see Grinnell, 1904, p. 25). As compared with 

 examples from eastern North America, they are distinctly more ashy- 

 hued anteriorly both above and below. Especially is this peculiarity 

 marked over the top and sides of the head. There is a slightly greater 

 general size in the case of the southwestern race. It is therefore prob- 

 able that the Colorado River birds are visitants from the mountains 

 of the southwest, whence kinglets of the same characters have been 

 secured in summer, rather than from the forests of the far north. 



There is also in the Museum a skin (no. 4272) taken by J. G. 

 Cooper at Fort Mohave, January 18, 1861. 



Polioptila caerulea obscura Ridgway 

 Western Gnatcatcher 



First seen at Needles, February 16; thenceforth noted regularly 

 at all stations along down the river until April 6, when the last were 

 noted ten miles below Cibola. As the specimens taken the first week 

 in April, when Polioptila plumb ea was nesting, showed no signs of 

 immediate breeding, it seems probable that the western gnatcatcher is 

 only a winter sojourner in the Colorado Valley. It occurred chiefly 

 in the bushes lining the desert washes leading back from the river; 

 a few individuals were met with in the mesquite and willow associa- 

 tions. 



The series of thirteen skins preserved (nos. 13874-13886) repre- 

 sent the following localities : California side, five miles south of Needles ; 

 both sides of the river at The Needles; California side at Riverside 

 Mountain and opposite Cibola ; and Arizona side, ten miles below 

 Cibola. 



