23 S GKm-ti^i.-L, The Sail Nicolas Rock Wren. [^^j^ 



ing ravines and the many gullies which cross the mesa at the sum- 

 mit of the island. It is not unreasonable, therefore, that a resi- 

 dent species on this isolated desert should become affected by 

 these peculiar conditions, and prove somewhat different from its 

 mainland counterpart. 



Salpinctes obsoletus pulverius, new subspecies. 



San Nicolas Rock Wren. 



Type, $ ad., in abraded breeding phimage, No. 2615, Coll. J. C, San 

 Nicolas Island, California, May 19, 1897. 



Measurements: length, 6.12; wing, 2.S0; tail, 2.20; tarsus, .85 ; culmen, 

 75 ; bill from nostril, .58; depth of bill at nostril, .18. 



Pattern of coloration similar to that of the mainland 5. obsoletus, but 

 entire plumage, especially the upper parts, suffused with ochraceous 

 or dust color, almost identical with the tint of the soil on San Nicolas 

 Island. 



Unfortunately no San Nicolas Rock Wrens in fresh fall plum- 

 age are available, and this yellowish coloration may be due in 

 part to the bleaching and abrasion of the plumage, but the charac- 

 ter is, nevertheless, quite apparent when compared with mainland 

 specimens in correspondingly worn plumage. This is probably 

 an instance of protective coloration, as foxes were found on the 

 island, and small birds must form a good share of their prey. 



The best character of pulverius, however, is the notably greater 

 size of the bill and feet, the measurements of which approach closely 

 to those of 6". guadeloupensis. The appended table shows the com- 

 parative measurements of specimens from the mainland and inter- 

 lying islands, as well as the eight adult specimens of pulverius 

 obtained on San Nicolas Island during the middle of May, 1897. 

 The specimens from San Clemente and Santa Barbara Islands 

 are intermediate in characters. 



Quite a large series of Rock Wrens from Western North 

 America are before me, and very little variation is to be found. 

 Southern California specimens are indistinguishable from those 

 taken in the Rocky Mountain region and eastward into Nebraska, 

 where, I believe, Say's type was taken. 



