SAN LUCAS NUTHATCH 21 



compared with the forest stands in which White-breasted Nuthatches 

 live in Upper California. This necessitates more extensive flights 

 from tree to tree in the usual course of foraging; and numerous 

 studies have shown that 'sharpness' as well as length of wing and 

 length of tail vary in direct correlation with extent of flight, whether 

 in migration or in day-by-day foraging." 



SITTA CASOLINENSIS LACUNAE Brewster 



SAN LUCAS NUTHATCH 



HABITS 



The San Lucas nuthatch was described by William Brewster (1891) 

 as "similar to Sitta carolinensis aculeata, but with the wings and 

 tail shorter, the black on the tips of the outer tail-feathers more 

 restricted." These characters are slight, but constant. The race was 

 not recognized at first by the A. O. U. Committee, but the fact that it 

 lives in a restricted habitat, near the southern tip of Baja California, 

 and the fact that it is separated from its nearest relative, in the San 

 Pedro Martir region, by some 600 miles of unsuitable terrain make it 

 seem worthy of recognition, as an isolated race. 



Of its distribution and haunts, Mr. Brewster (1902) writes: "The 

 St. Lucas Nuthatch is probably confined to the higher mountains south 

 of La Paz, where it was first detected by Mr. Belding in 1883. To 

 Mr. Frazar, however, is due the credit of collecting a sufficient series 

 of specimens to bring out the slight but nevertheless very tangible 

 differences which distinguish it from aculeata^ to which Mr. Belding 

 very naturally referred it. Mr. Frazar met with it only on the Sierra 

 de la Laguna, where, at all seasons, it is a rather common bird in- 

 habiting the pine forests at high elevations." 



Specimens collected by Frazar, early in May, were incubating; 

 but he evidently found no nests ; and, so far as 1 know, no one else has. 



SITTA CAROLINENSIS MEXICANA Nelson and Palmer 

 MEXICAN WHITE-BREASTED NUTHATCH 



In naming and describing this form, Nelson and Palmer (1894) 

 write : "The White-bellied Nuthatches from the mountains of south- 

 central Mexico present certain characteristics by which they may be 

 distinguished from either of the two recognized forms of the United 

 States. The Mexican bird has a beak averaging rather smaller than 

 that of Sitta caroUneruns from the eastern United States. With this 

 character it combines the color of the dorsal surface and dark markings 

 on tertials of S. aculeata, and differs from both northern forms in 

 having only the chin and throat pure white — the rest of the lower 

 parts in the present form being washed with a distinct ashy shade, 

 heaviest on the flanks and posteriorly." 



758066 — 48 3 



