MOUNTAIN BLUEBIRD 283 



These, like other bluebirds, are ordinarily gentle birds, but they 

 are able to defend their nests against aggressors and can become 

 aggressive themselves in the competition for nesting sites, or even 

 drive out the rightful occupants. Dr. Alden H. Miller (1935) tells 

 how he saw them drive a pair of hairy woodpeckers from their partly 

 finished hole and appropriate it for themselves: 



During the first day, June 5, commotions were frequently noticed at the 

 Woodpecker's tree. The trouble was instigated by a pair of Mountain Bluebirds 

 (Sialia currucoides) . Whenever the Woodpeckers alighted near the holes, both 

 Bluebirds attacked by diving at them, uttering harsh notes and apparently 

 snapping their bills. Such attacks often lasted five minutes. Evidently the 

 Woodpeckers were too much disturbed by them, possibly also by us, and deserted. 

 During the last two days at camp, no more fights were seen and the Bluebirds 

 were carrying nest material to the tree. The Woodpeckers stayed in the grove, 

 often close to camp, but did not go to the trees near the nest. Since the 

 Bluebirds were just beginning to build, the Woodpeckers were clearly the first 

 occupants and had been dispossessed. Irrespective of other factors which may 

 have contributed to their departure, there was no doubt of the intention of the 

 Bluebirds to displace them. 



On June 6 the female Bluebird went to an unfinished Robin's nest just over 

 the tent and settled in it, much to my surprise. She plucked material from the 

 margin and flew to her own nest hole. The Robins added to their nest later 

 that day. The Bluebird, symbol of happiness and gentleness, became to us a 

 different character, whose actions, viewed anthropomorphically, were aggressive 

 and piratical. Interspecific competition for nest material and nest site were 

 enacted before us. 



Voice. — The song of the mountain bluebird seems to have appealed 

 quite differently to various observers. Dawson (1923) evidently did 

 not hear it at its best, or did not appreciate it, for, after describing 

 its call and alarm notes, he says: "Other songs the birds have none. 

 * * * The entire song tradition, including the 'delightful warble' 

 attributed to the bird by Townsend, appears to be quite without 

 foundation." And that close observer of bird songs, Aretas A. 

 Saunders, writes to me: "In all my experience with this species in 

 Montana, I never heard it sing. On a number of occasious I camped 

 near nesting bluebirds and heard morning awakening songs of various 

 other birds, but nothing from the bluebird. It may be, as Weyde- 

 meyer suggests, that some individuals do not sing, or perhaps I 

 never happened to be awake at the right place and time to hear it." 



Kalph Hoffmann (1927) says: "The Mountain Bluebird at all 

 times is singularly silent. An occasional low terr is its commonest 

 note, uttered by a flock in flight. The only song which the writer 

 has heard is the repetition of a few short notes, like the syllables ke ku 

 or ku, ku, kit. When concerned about their young, the parents utter 

 a vigorous tschuk, tschuk." 



On the other hand, some observers have been more favorably im- 

 pressed. Francis H. AJlen says in his notes: "On several occasions 



