200 University of California Publications in Zoology L VoL - 12 



Dendroica aestiva brewsteri Grinnell 

 California Yellow Warbler 

 Appeared as a migrant through the willow bottom, individuals at 

 large being distinguished from the breeding D. a. sonorana by their 

 silence. Five specimens taken, nos. 13653-13657, bear locality and 

 date as follows: Male, California side, twenty miles north of Picacho, 

 April 12; male and female, same side, five miles northeast of Yuma, 

 May 4; male and female, same side, near Pilot Knob, May 9 and 6, 

 respectively. 



Dendroica aestiva rubiginosa (Pallas) 

 Alaska Yellow Warbler 

 A late migrant along the willows, secured only on the California 

 side near Pilot Knob ; two specimens : male, no. 13651, May 9 ; female, 

 no. 13652, May 14. 



Dendroica auduboni auduboni (Townsend) 

 Audubon Warbler 



Varyingly common as a winter visitant or transient on either side 

 of the river from the first day of our work, February 15, and from 

 our first station, Needles, until the last day of our work at our last 

 station, May 15, at Pilot Knob. Full-plumaged males were still noted 

 on the latter date, which would indicate unexpectedly late migration. 

 The species was seldom noted outside of the willow association, and 

 then only a short distance away, in the mesquite or a little beyond. 

 Twenty-five specimens were taken, nos. 13658-13682. 



There is also in the Museum a skin (no. 4257) taken by J. G. 

 Cooper at Fort Mohave, February 24, 1861. 



Dendroica nigrescens (Townsend) 

 Black-throated Gray Warbler 

 First seen April 2, on the California side opposite Cibola, a solitary 

 female. Next seen on the Arizona side ten miles below Cibola April 9, 

 a male ; then more frequently, sometimes in small droves with other 

 warblers, twenty miles north of Picacho, eight miles east of Picacho, 

 five miles north of Laguna, four miles south of Potholes and at Pilot 

 Knob. The last one was noted at the latter place May 9. The species 



