206 University of California Publications in Zoology [Vol.12 



two to one, for this period may therefore be near the truth. But it 

 is further observable from the data presented that pileolata was a 

 later migrant through this region than chryseola. 



Anthus rubescens (Tunstall) 

 Pipit 



At the time of our arrival at Needles, February 15, pipits were 

 numerous close along the river, both on the grassy areas near the 

 Indian camp and on the mud bars at the water's edge. They were 

 thenceforth observed through March at many points along the river on 

 both sides, especially when we were floating down from station to 

 station. They were still common the first week of April, opposite 

 Cibola. But none were seen later than April 8, when a single bird 

 was noted flying up river, ten miles below Cibola. 



Five specimens taken, nos. 13715-13719. 



Oreoscoptes montanus (Townsend) 



Sage Thrasher 



Observed only on March 23 and April 2 and 3, so probably a 

 transient purely. On the first specified date three were noted on the 

 California side, above Blythe. On the latter two days fully a dozen 

 were encountered on the same side opposite Cibola. In each case the 

 birds adhered closely to mistletoe-bearing mesquite and ironwood, 

 the latter extending up the desert washes. Four specimens taken, nos. 

 13793-13796. 



Mimus polyglottos leucopterus (Vigors) 

 Western Mockingbird 



Common early in the season all along the river on both sides. 

 Almost exclusively confined to the mesquite belt and to the ironwoods 

 a short distance up washes, especially where these trees were laden 

 with mistletoe. The berries of this parasite appeared to be the chief 

 or only food of the mockingbird. 



Mockingbirds were especially common the last week in February 

 in company with robins, bluebirds, and phainopeplas in the mesquite 

 belt near Mellen, Arizona. The day (March 15) we floated down 

 from our last station above the mouth of Bill Williams River to 

 Parker, we heard the singing of mockingbirds from either side of the 



