508 ANIMAL LIFE IN THE YOSEMITE 



belong to the California race (gambeli), but one, at least, is referable to 

 the subspecies {excuhitafides) inhabiting the Great Basin. This indicates 

 that some of the shrikes are given, just as are certain other birds of the 

 arid interior, to wandering over to the west slope of the Sierra Nevada 

 during the season of storms and snow in the Great Basin region. 



Near Lagrange on May 6, 1919, a family of California Shrikes was 

 found near the home tree, a blue oak on a hill above the county road. The 

 two parents were accompanied by five lusty youngsters, the latter having 

 left the nest only a day or two previously. From time to time the 

 youngsters implored their parents for food by uttering quavering peevish 

 cries, and at the same time they quivered their wings in the manner common 

 to many young birds. The young at this age showed fine brown barrings 

 on the whitish under surface, the white on their wings and tail was clouded 

 with brown, and the plumage looked softer, more fluffy than that of the 

 adults. The nest was about 9 feet above the ground in the foliage of a 

 dense blue oak, and had been much flattened by its late occupants. The 

 rim of the nest and adjacent foliage of the oak were much spattered with 

 excrement. This suggests that a bird of prey, which the shrike is in habits 

 if not in systematic position, does not need to keep the location of its nest 

 a secret after the young are hatched. A couple of days later, two members 

 of this brood were seen perched on fence posts about 150 feet apart, along 

 the roadway. They were watching an adjacent field. Parental super- 

 vision had ceased and the young birds had begun to live independently. 



Western Warbling Vireo. Vireosylva gilva swainsoni (Baird) 



Field characters. — Two-thirds size of Junco; tail shorter than body. Plumage grayish 

 green with no highly contrasted markings ; a light line over eye ; no light bars on wing. 

 (See pi. 50fe.) Movements slow as compared with warblers; keeps usually within crown 

 foliage of trees. Voice: Song of male a sustained and voluble warble uttered at short 

 intervals; both sexes give a throaty or burred call note, szhec or zree. 



Occurrence. — Summer visitant in Upper Sonoran, Transition, and Canadian zones 

 on both sides of Sierra Nevada; commoner on west slope. Observed from Pleasant 

 Valley and near Lagrange eastward to Porcupine Flat and Merced Lake; also at Walker 

 Lake and Mono Lake Post Office. Frequents deciduous trees chiefly, most often near 

 streams, foraging from 10 to 60 feet above ground. Solitary except when pairs are 

 caring for broods. 



The Western Warbling Vireo is the most widely distributed and the 

 commonest of the four species of vireo occurring in the Yosemite section. 

 While usually found in deciduous trees and in the general vicinity of 

 streams it is at times observed well away from water and is occasionally 

 to be seen or heard high in tall coniferous trees. 



Vireos as a group are birds of deliberate mien. When an individual 

 is discovered, as often happens, in the same tree with some one of the 



