1014 1 Grinnell: Mammals and Birds of the Colorado Valley 205 



attention to a single individual was enough for unmistakable recog- 

 nition of notes or songs of Abert towhee, flicker, kingfisher, Bullock 

 oriole, and tanager. The chat is here a far better mocker than the 

 mockingbird itself. 



Wilsonia pusilla pileolata (Pallas) 



Alaska Pileolated Warbler 



Appeared commonly as a migrant through the riparian strip. Six- 

 teen specimens (nos. 13736-13751) were taken, from April 19 to May 

 12, inclusive, representing the following localities : California side, 

 eight miles east of Picacho, April 19 and 20; Arizona side, five miles 

 north of Laguna, April 21, 24 and 25; California side at Potholes, 

 April 27 ; same side, four miles south of Potholes, May 1 and 2 ; same 

 side, five miles northeast of Yuma, May -4 ; same side near Pilot Knob, 

 May 8 and 12. 



Wilsonia pusilla chryseola Ridgway 

 Golden Pileolated Warbler 



Common as a migrant, through the riparian strip. First seen 

 March 9 and 10, one each day, on the California side in Chemehuevis 

 Valley. Next noted March 20, one taken, near Riverside Mountain ; 

 thenceforth of almost daily observation in suitable places at nearly all 

 stations until May 2, when the last one with certainty identified was 

 taken on the California side four miles below Potholes. Intermediate 

 points and dates of capture were: California side above Blythe, March 

 23 ; Arizona side below Ehrenberg. March 26 ; ten miles below Cibola. 

 Arizona side, April 7, 8 and 9 ; California side twenty miles north of 

 Picacho, April 11 and 12 ; same side, eight miles east of Picacho, 

 April 18 and 20; Arizona side, five miles above Laguna, April 25 and 

 26; four miles below Potholes, April 30, as well as May 2, as noted 

 above. The series of specimens taken consists of seventeen examples 

 (nos. 13752-13768). 



At times pileolated warblers were numerous in tracts of willow, 

 but since it was impossible to distinguish between the race pileolata 

 and the race chryseola without shooting, the proportion present of 

 these two forms between April 19 and May 2 could not be judged. All 

 individuals shot were, however, preserved. Between these dates, thir- 

 teen pileolata were taken aud seven chryseola. This proportion, nearly 



