188 University of California Publications in Zoology [Vol. 12 



ground in a mesquite. These situations are representative of the 

 average predilections of the species in other regions. 



Thirty-two specimens of the phainopepla were preserved, nos. 

 13478-13509. There are in the Museum five specimens (nos. 4196- 

 4200) taken by J. G. Cooper at Fort Mohave, December 24. 1860, 

 and January 17 to April 13, 1861. 



Lanius ludovicianus excubitorides Swain son 

 White-rumped Shrike 



Shrikes proved unexpectedly scarce in the region explored. In 

 spite of our special exertions, only four specimens were secured, nos. 

 13386-13389. Besides these, there are two more in the Museum (nos. 

 4205, 4206) taken at Fort Mohave by J. G. Cooper, April 18, 1861, 

 and December 26, 1860. The six specimens show much variation 

 among themselves, and not enough of uniformity in any one character 

 to suffice for recognition, as I had anticipated, of a Lower Sonoran 

 form of the excubitorides type different from an Upper Sonoran or 

 Transition one. It is quite possible that some of the variation 

 exhibited, as in degree of paleness and size and outline of bill, may 

 be due to the fact that in the series some individuals were resident 

 birds and others winter visitants from the Great Basin region. At 

 any rate, the small series is inadequate as a basis for any satisfactory 

 study of subspecific status. I am therefore including all under the 

 name excubitorides, with the suggestion that it will probably be 

 found after more extensive collections are worked over that further 

 subspecific separation will have to be made. 



Our first specimen was taken February 15 at Needles, and like 

 several other birds of that neighborhood, the plumage was seriously 

 discolored by coal smoke. Another was taken five miles below Needles, 

 February 22, and one additional pair seen there. A pair was seen 

 on the Arizona side near Mellen, February 24 and 27. Next noted 

 at Ehrenberg. where a lone individual was secured March 28 ; next on 

 the same side five miles above Laguna, where one was taken April 24. 

 Last seen May 15 near Hanlon Junction, just north of Pilot Knob. 

 In all these cases, the shrikes were in desert washes from a half-mile 

 to two miles from the margin of the riparian belt. As usual they 

 chose the most open ground productive of an adequate food-supply. 



