462 ANIMAL LIFE IN THE YOSEMITE 



flight ; then, after a pause, and some hopping about from branch to branch, 

 it descends again to the ground near by. If badly scared the bird will 

 make off to a distance, though usually going from one tree to another 

 rather than making a continuous, direct flight in the open. 



While foraging on the ground a junco opens and shuts the tail slightly 

 from time to time, so that the white margins show for an instant. Upon 

 taking flight either from the ground or a tree the bird spreads its tail 

 widely and then the white shows broadly and conspicuously. Some natural- 

 ists believe that the bird's flashing of these contrasting areas serves to 

 apprize other members of the species of the particular individual 's location 

 and of the direction taken by it when it moves off ; any threatening danger 

 seen by one bird may thus be reported to other juncos in the vicinity 

 which, in turn, seek safety. Accompanying the display of white when an 

 alarmed junco flies up are the well-known call notes given in rhythm with 

 the wing-beats and movements of the tail; and these notes are believed 

 to be of similar purport. The sense of hearing is thus brought into service 

 to supplement that of sight. 



The song of the male junco is to be heard throughout the spring and 

 early summer months ; it usually ceases some time in July. It is a quaver- 

 ing trill, pleasing to the human ear, given rapidly and possessing a tinkling 

 quality. The syllables are practically alike, eetle, eetle, eetle, eetle,- on 

 about the same key, but with the intensity lessening toward the end. In 

 spring the male gives his song at practically any hour of the day, perhaps 

 not so much at dawn and dusk as during the mid-day hours. Yet we have 

 heard it as early at 5 :15 a.m. (June 2), in Yosemite Valley, and sometimes 

 the birds break out in song in the middle of the night. The sharp call 

 note, seep or tsick, uttered by both sexes, is usually repeated several times 

 as the birds rise from the ground, and if given while foraging there, its 

 utterance is often accompanied by momentary flashing of the white outer 

 tail feathers. A heavier note, of alarm, is also given, tsup. 



The courting of the junco is not so elaborate or varied a performance 

 as that of some birds. The pursuit of females by males or of rival males 

 by one another may occasionally be observed, but for the most part the 

 birds are rather quiet. Occasionally males either on the ground or perched, 

 when females are close by, will hold the tail spread for some seconds so 

 that the white margin shows forth with extraordinary brilliance. The 

 song seems to be the principal factor in courting. In order to study this 

 subject satisfactorily, an observer would need to keep track of flocks just 

 before they break up in the spring and then watch the behavior of the 

 pairs during the whole course of the development of the mating instincts. 



When the first rush of human travelers reaches the Yosemite region 

 in May the juncos are preparing to nest, and by early June many pairs 



