248 



THREE WESTERN BIRD GROUPS 



coo. A chittering note, possibly of alarm, is produced by a 

 rapid striking of the mandibles. 



From May 14 to 17, we camped at the mouth of Pima 

 Canon, in the Santa Catalina Mountains, about twelve miles 

 from Tucson. After crossing the sandy bed of the Santa 

 Cruz Valley, where the creosote bush (Covillea) now cov- 

 ered with innumerable little downy, white seed-balls, was 



Mourning Dove Nesting in Cholla 



the prevailing plant, we ascended the rocky mesa where the 

 various species of cactus grow more luxuriantly than we 

 had found them in the vicinity of Tucson. Birds, too, were 

 more abundant and we added a number of species to the list 

 of those observed about the city. 



About a mile above our camp, excellent water could still 

 be found in a stream flowing through and over the rocks in 

 the bottom of the canon, and this proved a source of attrac- 

 tion to many species of birds. 



Morning and evening an almost continuous flight of 

 Mourning and White-winged Doves passed our camp in 

 going from the desert to the water, up the canon and back 



