514 ANIMAL LIFE IN THE YOSEMITE 



no bright crown-patch such as is worn by the male kinglet. In demeanor 

 the two birds are at most times strikingly different, and the voices are not 

 likely to be confused at all. The deliberate vireo occasionally flutters 

 its wings but never so frequently or nervously as does the smaller bird. 

 During the winter season both of these birds are to be found in the oaks, 

 and so, on occasion, may be compared in life, side by side. 



The range of the Hutton Vireo within the Yosemite section is not 

 extensive. The westernmost station at which we observed the species was 

 Blacks Creek, west of Coulterville, and the easternmost was the talus slope 

 on the north side of Yosemite Valley, near Rocky Point. In the winter 

 of 1914 (December 28), one was recorded at 4500 feet altitude on the 

 Big Oak Flat road, and on October 21, 1915, one was found at Gentrys, 

 5800 feet, also on that road. The species was seen in greatest numbers 

 at El Portal, probably because of the abundance of evergreen oaks in the 

 vicinity. 



The restriction of the Hutton Vireo to oak trees seems to be practically 

 complete; not one of our ten recorded observations of the species list it 

 as being seen elsewhere than in one or another kind of these trees. It 

 forages occasionally in black oaks, but more commonly in the non-deciduous 

 oaks. In Yosemite Valley, individuals were discovered by following up 

 the characteristic monotonous drawling song, in June, July, and December. 

 All observed were at the lower end of the valley, west of Yosemite Falls. 



California Ijeast Vireo. Vireo belli pusillus Coues 



Field characters. — Less than half bulk of Junco or Linnet. Plumage appearing light 

 gray above, whitish beneath; a single inconspicuous light bar on wing (pi. 50d). Move- 

 ments quicker than those of other vireos but less nervous than those of warblers or 

 kinglets. Voice: Song of male, a rapidly uttered series of three or more warbling notes 

 ending in a short questioning note, a pause, then the series repeated with downward 

 inflection. 



Occurrence. — Summer visitant locally in Lower Sonoran Zone. Common at Snelling 

 and below Lagrange; one pair found at Pleasant Valley May 22 and 23, 1915. Keeps 

 low (6 feet or less from ground) in willow and other thickets along streams and sloughs. 

 In pairs or solitary. 



The California Least Vireo dwells in the dense thickets of willows and 

 other plants which grow along the lower courses of the Merced and 

 Tuolumne rivers, chiefly west of the foothills. In size, coloration, voice, 

 and habits it is well set off from the other three species of vireos in the 

 Yosemite section, so that chance of confusion with them is slight. 



The Least Vireo is decidedly smaller than any of the other species of 

 vireos; it is less fluffy in appearance than the Hutton Vireo, the next in 

 point of weight. Its grayish tone of coloration above, single wing bar 

 (pi. 50d) scarcely discernible at a distance, and whitish under surface, 

 taken together distinguish it from its relatives. 



