412 University of California Publications in Zoology. [Vol. 7 



Oporornis tolmiei (J. K. Townsend) 

 IMacGillivra}^ Warbler 



Distribution. — Occurred quite generally in suitable situations. 

 Noted from Upper Sonoran at 4100 feet altitude to Transition at 

 8500 feet. It was doubtless breeding in Transition. 



Habits. — A squeaking sound made by the lips was often suffi- 

 cient to coax Oporornis from his favorite foraging grounds, the 

 willow thickets and chinquapin patches (Castanopsis). One 

 could often trace an individual by attending closely to the little 

 call-note "chick!" ''chick!", the only difficulty being that fre- 

 quently the intervals between its times of utterance became long 

 drawn out. The song of the MacGillivray warbler resembles 

 those of the yellow warbler and lazuli bunting, but is nearer that 

 of the latter, though it has a lighter, airier quality. One indi- 

 vidual was seen with a large worm in its mandibles. 



On the morning of July 9 two pairs were observed in the rank 

 undergrowth over some springs surrounded by a thick grove of 

 quaking aspens at 7000 feet altitude on Big Creek. One pair 

 became highly excited, the female especially. Both birds ap- 

 proached to within a few feet of the collector. Though these 

 signs indicated a nest in the vicinity, none was discovered. A 

 Juvenal was secured on July 15. 



Geothlypis trichas occidentalis Brewster 

 Western Yellowthroat 



Not common anywhere. A few individuals were noted at 

 Quinn River Crossing, Big Creek Ranch, and Virgin Valley. 

 Zonally the species was found in Upper Sonoran. 



While ordinarily the yellowthroat was exceedingly suspicious, 

 one was sometimes able, by making a peculiar sound with the 

 lips, to coax the bird from its hiding place into plain view. 



Eleven examples of the species (nos. 8509-8518, and 9205) 

 were preserved. 



