RIVOLI'S HUMMINGBIRD 323 



grayish, and under parts darker, with entire sides distinctly glossed 

 with bronze-green." These characters are well shown in a large 

 series that I have examined. Four young males, collected in July, 

 all show more or less green in the throat, but only one, taken July 25, 

 shows any violet in the crown. Others, taken in September and on 

 November 1, show further progress toward maturity; and two young 

 males, taken July 9 and 12, are still in first winter plumage. 



Food. — Not much has been published on the food of Rivoli's hum- 

 mingbird. Bendire (1895) mentions a boreal honeysuckle {Lonicera 

 invohicrata) as one of the plants from which Dr. Fisher saw them 

 gleaning food, and says: "Thej^ are said to be especially fond of 

 hovering about the blossoms of the mescal {Agave americana) ; these 

 are generally infested by numerous small insects, on which they feed, 

 and, like all our hummingbirds, they are exceedingly greedy and 

 quarrelsome, chasing each other constantly from one flower stalk to 

 another." 



He quotes Mr. Price as saying that "during the flowering season it 

 feeds extensively in the flowers of the Agave farryi in the Huachuca 

 Mountains. In the Chiricahuas I have found it early in the mornings 

 in open glades, feeding on the flowers of an iris." Mr. Poling (1890) 

 mentions its fondness for the bright red and yellow flowers of the 

 mescal on the slopes of the Huachucas. 



Probably any brightly colored flowers, to which insects are at- 

 tracted, are resorted to by this and other hummingbirds, the insects 

 feeding on the nectar and the hummingbirds feeding on both insects 

 and nectar. Mr. Fowler (1903) saw it feeding "among some scarlet 

 geraniums in a large flower-bed." 



Three stomachs examined by Cottam and Kjiappen (1939) con- 

 tained leaf bugs, plant lice, leafhoppers, parasitic wasps, beetles, flies, 

 fragments of a moth, and undetermined insects and spiders. "No 

 fewer than eight species of insects and spiders were noted in one 

 stomach." Spiders made up 31.66 percent and flies 26 percent of the 

 whole food. 



Behavior. — While I was collecting birds with Frank Willard in 

 the Huachuca Mountains, he asked me not to shoot any blue-throated 

 hummingbirds, as they were so rare, and I agreed to respect his 

 wishes. One morning we were sitting on a steep hillside watching 

 some large hummingbirds that were chasing each other about in the 

 tops of some tall pine trees on the slope below us. I wanted a 

 Rivoli very much, so he pointed out one that I could shoot, but, 

 much to his disgust, when we picked it up, it proved to be a male 

 bluethroat. This illustrates the similarity of the two species in gen- 

 eral appearance. 



The flight of Rivoli's hummingbird is somewhat different from that 

 of the small hummers that I have seen. It is a large, heavily bodied 



