406 ANIMAL LIFE IN THE YOSEMITE 



chack-ing harshly, and scolding and whistling incessantly. If the observer 

 makes a 'screeping' noise with the lips, the males fly up and hover over 

 the nest site, with wings and tail widely spread, as if trying to appear as 

 large and absorbing of attention as possible. The females join these 

 demonstrations at first, but soon retire and leave their otherwise unoccupied 

 mates to continue the protests. 



As mentioned above, a single young bird, nearly fledged, was found 

 in one of the nests examined at Lagrange. When an effort was made to 

 lift this bird from the nest he clung tenaciously to it and each of his sharp 

 claws had to be released in turn from the lining material. Later, when 

 released over dry ground, he flew in a direct line toward the nearest patch 

 of green, a willow tree, and the instant he touched the foliage he seized 

 the latter with clenching claws and hung there until disengaged again. 

 The instinctive traits here exhibited must be of positive value to the young 

 Red-wings as safety measures, just after they leave the nest. The face 

 of this young bird was almost bare of feathers. The query arises as to 

 whether this feature in the young Red-wing is adaptive, for better hygiene 

 and sanitation during life in the nest, or whether it is an ancestral trait, 

 showing the relationship of the Red-wing to certain tropical American 

 members of the family. Furthermore, the ear coverts of the young bird 

 had scarcely begun to grow out, and the under wing coverts were likewise 

 undeveloped, although the bird was otherwise nearly fledged. The bird's 

 first need is for feathers to sustain flight; less important or accessory 

 portions of the plumage make their appearance later on. 



Observation along the bank of the Tuolumne River below Lagrange 

 on May 7, 1919, disclosed the fact that the Bi-colored Red-winged Black- 

 birds in that vicinity were using the river as a fly-way between their nests 

 and some rich forage ground up the river. Thus, in fifteen minutes (2:15 

 to 2:30 P.M.), 49 birds, all females, were seen to fly up the river past a 

 selected post of observation. Fifteen went singly, and 12 in two's, while 

 there were 2 groups of 4 and one each of 3 and 11, So far as could be 

 seen none going in this direction had anything in the bill. In the same 

 interval of time 38 birds, all females, were counted going down stream. 

 All the latter seen closely were carrying what looked like cutworms. The 

 grouping of these birds was as follows: 25 singles, 5 in groups of 2 each, 

 and one of 3, The fact that fewer were seen going down the river than 

 up was probably accounted for by the fact that some individuals on the 

 return journey cut across a gravelly bench beside the river at this point 

 and went down overland behind a line of willows in a more direct course 

 to their nests; 2 or 3 were glimpsed in such a course. These observations 

 prompted the following conclusions: (1) Somewhere doAvn the river there 

 was a breeding colony of Red-wings; (2) many young in this colony were 



