BIRDS OF THE TRES MARIAS ISLANDS. 37 



numerous. Two specimens were taken on Maria Madre, May 7, and 

 a single specimen was shot on Isabel Island, April 22; the latter was 

 undoubtedly a straggler from the mainland, since Isabel is a waterless 

 island. 



ColumbigaLina passerina pallescens (Baird). Mexican Ground Dove. 



These pretty little doves were common on Maria Madre and Maria 

 Magdalena, but were most numerous about old fields and in the settle- 

 ment on the former island. The series of specimens taken on Maria 

 Madre appears to be identical with the birds of the adjacent mainland; 

 seven males from the islands average as follows: Wing, 87.4; tail, 61.8; 

 culmen, 11.6; tarsus, 16.6. 

 Cathartes aura (Linn.). Turkey Vulture. 



Generally distributed, and very common about the settlement on 

 Maria Madre. 



Buteo borealis fumosus Nelson. Tres Marias Red-tailed Hawk. 



Jiuteo borealis var. montana Grayson, Proc. Boston Soc. Nat. Hist., XIV, p. 268, 1871 



(part). 

 Buteo borealis var. calurus Lawr., Mem. Boston Soc. Nat. Hist., II, p. 301, 1874 



(part). 

 Buteo borealis fumosus Nelson, Proc. Biol. Soc. Washington, XII, p. 7, 1898. 



Colonel Grayson records this as a common species. We found a 

 few living along the canyons that score the slopes of Maria Madre. 

 They were very sparsely distributed and only some twelve or fifteen 

 individuals were noted; two or three were seen on Maria Magdalena 

 and none on Maria Cleofa. They were not at all shy, and whenever 

 found perched on a tree were readily approached within gunshot. 

 They feed mainly upon iguanas and rabbits, both of which are common' 

 on the two larger islands. Nothing distinctive was noted about the 

 habits of these hawks. They are uniform in color, and differ more from 

 the mainland forms than does B. borealis socorroensis, although the 

 latter is from an island much farther out at sea. 



The adult female of fumosus has some heavy shaft streaks of dark 

 brown on the chest, but these are not heavy enough to form a well- 

 defined dark area as is often the case in calurus. 



Description of an immature male ( ?) from Maria Madre : Upper surface 

 almost uniform blackish brown; tail mainly of same color, but crossed 

 by nine narrow, irregular lighter bands; a light area on the throat, 

 where the feathers have narrow blackish shaft lines and broad, dull 

 white borders: breast and sides of neck dull, dark brown, with dull, 

 rusty edgings to feathers on latter area; middle of breast paler; feathers 

 on lower breast and flanks blackish brown, with irregular whitish spots; 

 abdomen and lower tail coverts dull brownish, paler than flanks, with 

 pale butty barring; some feathers of tibia buffy or heavily barred with 

 bntt'y, but mostly like those of lower breast. 



