THE BIRDS OF CLIPPERTON AND COCOS ISLANDS 



515 



SULA PISCATRIX WEBSTERI Rothschild. 



Sula piscator Ridgway, Proc. U. S. Nat. Mus., xix, p. 598, 1896 (Gala- 

 pagos). 



Sula ivebsteri Rothschild, Bull. Brit. Ornith. Club, vil, p. 52, May, 1898 

 (Clarion Island). — Anthony, Auk, xv, p. 311, Oct., 1898 (Rivillagigido 

 Islands). 



Sula piscatrix websteri Rothschild and Hartert, Novitates Zoologicas, vi, 

 p. 177, 1899 (Clarion Island and Galapagos Islands). 



Range. — Rivillagigido Archipelago, Cocos Island, and Galapagos 

 Archipelago. 



Adult Male. — Cat. No. 4273, Stanford University Museum, from 

 Culpepper Island, Galapagos, December 10, 1S98. Primaries, sec- 

 ondaries, alula, greater wing coverts and some of under wing coverts 

 dark sooty-brown. Rectrices above and below lighter brown, the 

 barbs with a hoary-gray bloom on their upper edges ; the median tail 

 feathers pale toward the tips. All other parts of the plumage plain 

 w^hite. Shafts of the tail feathers white. Shafts of under wing cov- 

 erts brown. 



Bill (in life) pale blue. Bare skin about base of bill pink; circum- 

 ocular region blue, darker than the bill and darkest immediately about 

 the eye; an uncolored spot just before the eye. Membrane between 

 the rami of the lower mandible purplish-black, mixed with flesh- 

 color basally, entirely of this color anteriorly. A narrow black band 

 extending upward at base of the mandible. Feet red. (Specimen 

 from Clarion Island, August.) In dried specimens the bill varies from 

 horn-yellow to dark reddish with a blackish tip, showing almost no 

 trace of the blue color of fresh specimens. 



Immature Feinale. — Cat. No. 4,277, Stanford University Museum, 

 from Culpepper Island, Galapagos, December 10, 1898. Plain ashy 

 brown, darker above and on the wing and tail feathers, dusky on the 

 primaries, palest on the head and neck. Forehead obscurely spotted 

 with dusky. Shafts of median tail feathers yellowish-white. 



We found this bird abundant in July at Chatham Bay, Cocos 

 Island, where it perched in the tops of tall trees that overhang the 

 water everywhere along the shore. We did not find it on Clipperton 



