618 ANIMAL LIFE IN THE YOSEMITE 



Western Bluebirds winter along Smith Creek east of Coulterville, 

 according to Mr. Donald D. McLean. We found the birds in moderate 

 numbers in the San Joaquin Valley below Lagrange and at Snelling, in 

 December and January. 



Some censuses will now be given which will serve to show how the 

 numbers of the birds vary as to locality and season. At Pleasant Valley 

 a 5-hour census on May 24, 1915, yielded 20 Western Bluebirds, practically 

 all of them being in pairs. On February 27, 1916, a 31/2 hour trip over 

 the same territory gave count of 42 birds, most of which were in flocks. 

 Twenty-three were noted in 3 hours spent north of Pleasant Valley on 

 December 4, 1915, and 15 in 2 hours near Lagrange on December 12, 1915. 

 On November 26, 1914, 20 or more were noted at Fort Monroe; fully 125 

 were congregated in oaks near the lower (Yosemite) end of the Big Oak 

 Flat road on December 28, 1914; 75 of these were flushed at one time. 

 In December, 1914, the aggregate population of Western Bluebirds in 

 Yosemite Valley was believed to outnumber that of all other birds com- 

 bined. The birds at Pleasant Valley in December were in groups of 7, 5, 

 5, 2, 2, and 2. 



In the nesting season the two bluebirds of a pair stay close together, 

 usually within a few yards of one another. Then in late May or early 

 June the young are led abroad and the family group stays together for 

 some time. The manner of association during the season of molt has not 

 been observed, but by September flocks have formed which include both 

 adult and immature birds, and in this fashion they spend the winter. 

 The flocks, in observed instances, included from 6 to 25 members. Some- 

 times other birds are associated. In Yosemite Valley we saw Western 

 Bluebirds in company with Audubon Warblers on one or more occasions, 

 and Mr. C. W. Michael (MS) reports Western and Mountain bluebirds 

 together there during November of 1920. Western Bluebirds and Robins 

 are frequently seen together during the winter months though the two 

 do not flock with each other in the usual sense of the word. 



In general demeanor the Western Bluebird is much like other members 

 of the thrush family, being of deliberate or even phlegmatic temperament. 

 When perched it sits quietly, not hopping about as do many small birds 

 such as sparrows and warblers. It ordinarily seeks a perch which will 

 command a wide field of view, as on some upper or outer branch of a 

 deciduous tree. Some time is spent, especially during the summer months, 

 in catching insects, either by darting after such as pass in the air or bj- 

 pouncing down from a fence post or low branch onto grasshoppers and 

 other ground-dwelling species. Upon taking to flight bluebirds make off 

 in the open, high in the air, uttering their soft call notes now and then as 

 they fly. The high course of flight and the repeated flight calls are sug- 

 gestive of the behavior of linnets under similar circumstances. Sometimes 



