SLENDER-BILLED NV THATCH 565 



Occurrence. — Resident in Upper Sonoran Zone on west slope of Sierra Nevada where 

 recorded from near Lagrange and Merced Falls eastward to Smith Creek, east of 

 Coulterville; present in Transition and Canadian zones on west slope except during 

 midwinter; also found east of mountains (Mono Mills) during summer season. Lives 

 low on trunks and larger branches of both coniferous and broad-leaved trees. Solitary. 



The Slender-billed Nuthatch is the largest of the three nuthatches found 

 in the Yosemite region. Because it is fairly common and does its foraging 

 chiefly on the lower parts of the trees, it is the species most likely to be 

 seen. 



The Slender-billed Nuthatch enjoys a wide distribution in the Yosemite 

 section. It is resident in the blue-oak belt of the western foothills, and 

 is found also, at least from spring until early winter, in the Transition 

 and Canadian zones. Its range on the west slope extends from near 

 Lagrange and Merced Falls eastward. The easternmost summer record 

 w^as made at Mono Meadow, a few miles south of Glacier Point. In the 

 early fall, as is shown by records from Ten Lakes, McGee Lake trail, and 

 the Clouds Rest trail near Little Yosemite Valley, the birds invade the 

 higher mountains. On the east slope of the mountains Slender-billed Nut- 

 hatches were found at Mono Mills on June 7 and 10, 1916, and at Williams 

 Butte, Walker Lake, and Warren Fork of Leevining Creek, in the fall 

 of 1915. 



The three species of nuthatches of the Yosemite section agree closelj^ 

 not only in general form of bill, wings, and tail, but also in having bluish 

 gray backs and in possessing white spots on the outer tail feathers. (See 

 pi. lOe, /, g.) There are, however, sharp diflferences between these birds, 

 to be seen if looked for with some little care. The Slender-billed is about 

 twice the size of the Red-breasted and Pigmy nuthatches and the entire 

 side of its head or ' cheek ' is white ; the under surface of the body also is 

 pure white. In the other two birds the side of the head at least down to 

 the eye is dark, and the lower surface is not clear white. The adult male 

 Slender-billed has the top of the head silky black, whereas in females this 

 area is much duller. This difference in coloring affords a means for dis- 

 tinguishing the sexes in the field. 



The word nuthatch comes to us from the Old World where it was first 

 applied to a European relative of our birds which has the habit of wedging 

 nuts into crevices and then hacking them open. Our nuthatches do con- 

 siderable pounding with their bills both in digging their nest holes and 

 in breaking up food materials. Nuthatches, creepers, and woodpeckers 

 get most or all of their living on the trunks and branches of trees, but 

 the representatives of each of these groups go after their food in different 

 ways. The woodpeckers dig out grubs and insects which burrow in or 

 beneath the bark, while the other birds mentioned get eggs, larvae, and 



