1914] Grinnell: Mammals and Birds of the Colorado Valley 191 



Vermivora luciae (Cooper) 

 Lucy Warbler 



First seen March 10, on the California side in lower Chemehuevis 

 Valley; there were three individuals foraging' quietly in company with 

 Audubon warblers and ruby-crowned kinglets in the sunlit summits 

 of willows. The one shot was a male. The Lucy warbler is undoubt- 

 edly absent from the region in winter, and the above observation 

 indicates approximately the date of its arrival. 



Next noted March 14 on the Arizona side above Bill Williams 

 River. Here, at least four males were located in mesquites, and as 

 they were in full song and spaced apart, had doubtless settled upon 

 breeding locations. The song is unmistakable, as far as all other birds 

 of southern California and Arizona are concerned. It resembles the 

 song of the Sonora yellow warbler in length and frequency of utter- 

 ance and somewhat in quality, but with a distinct hurried and lisping 

 effect reminding one of the song of the Lazuli bunting. 



On the California side, both at Riverside Mountain and above 

 Blythe, Lucy warblers were numerous, and very closely confined to the 

 narrow belt of mesquite. The singing males, each representing the 

 forage area and nesting site of a pair, were spaced out very uniformly, 

 so that an estimated strip of about 200 yards in length belonged to 

 each. The birds foraged out to a limited extent from the mesquites 

 towards the river into the arrowweed and willows, and away from 

 the river at the mouths of washes into the ironwoods and palo verdes. 

 But the metropolis was always most emphatically the mesquites. At 

 this time, March 18 to 23, the mesquites were just coming into leaf, 

 and the new yellow-green foliage was prolific of insect life and formed 

 both a productive food-source and an excellent cover for a low-foliage 

 feeder, such as the Lucy warbler pre-eminently is. 



At Ehrenberg, Arizona, the last week of March, the species was 

 common, as also on the California side opposite Cibola the first week 

 of April, and on the Arizona side, again, ten miles below Cibola. At 

 the latter point a nest, nearly completed, was found April 8. It rested 

 upon a loosened skein of bark on the under side of a slanting mesquite 

 trunk, and was five feet above the ground. 



On the California side the Lucy warbler was fairly common in 

 the vicinity of our stations twenty miles above and eight miles east 

 of Picacho, at both points being closely adherent to the mesquite strip. 



