426 BULLETIN 17 6, UNITED STATES NATIONAL. MUSEUM 



begin to show more or fewer metallic-purple feathers in the gorget; 

 slight advance toward maturity seems to continue during fall and 

 winter, until the prenuptial molt, late in winter or early in spring, 

 produces the fully adult plumage. The young female is like the adult 

 female, but the upper parts are more bronzy and the feathers are 

 indistinctly margined with dull brownish. 



Pood. — The calliope, like other hummingbirds, feeds on nectar 

 from flowers and on the minute insects and small spiders that fre- 

 quent the flowers. The sweet nectar in the flowers undoubtedly 

 attracted the insects, but whether it was the nectar or the insects that 

 first attracted the hummingbird is an open question ; the insects may 

 have been the original objects of their search, and the nectar devel- 

 oped a taste for sweets. Any brightly colored flowers are likely to 

 attract these birds, but they seem to show a preference for red flow- 

 ers, such as the scarlet paintbrush and the red columbine. The 3'ellow 

 flowers of Mimulus implexiis also furnish a food supply for them. 

 And Grinnell, Dixon, and Linsdale (1930) write: "In early May in 

 the vicinity of Mineral this species appeared to have just one plant, a 

 species of lousewort {Pediculai^is seiniharhata) , which it frequented. 

 The flowers grew on long spikes from leaf rosettes under snow-brush. 

 The hummers had to fly down among close-set twiggage of the bushes 

 to get at these flowers. Often they alighted almost on the ground 

 to get at the horizontal tubes. By May 28 they were very active in 

 a tract of blossoming manzanita at 6000 feet, even among snow banks. 

 A female was seen at a snow-plant {Sarcodcs) where these plants 

 were first coming up, on June 26, beneath red firs." 



The calliope hummingbird also hawks for insects on the wing, 

 much after the manner of flycatchers ; probably any small insect that 

 becomes available is acceptable, but small species of Diptera, Hyme- 

 noptera, or Coleoptera seem to be most often taken. Milton P. 

 Skinner tells me that he has seen one perched on a willow, turning 

 its head and upper body from side to side with an almost clocklike 

 motion, while watching for insects. Others have noticed its sallies 

 into' the air for passing insects, which its keen eyes have detected. 



Behavior — Several observers have written of the territorial rela- 

 tions of this hummingbird and of its aggressiveness in defending its 

 nesting territory and its foraging range. Grinnell, Dixon, and Lins- 

 dale (1930) write: 



On a six-acre plot of ground where the activities of individual birds were 

 observed closely through several nesting seasons four separate males kept 

 distinct "stands" each for itself. As nearly as could be determined all the 

 females that were seen on this plot were visitors whose nests were off in a belt 

 of lodgepole pines on Battle Creek Meadows. Females came onto the plot to 

 forage about flowers (Castilleia) that were plentiful there, and were then 

 shown attention by the males. 



