"2 I A Oberholser, The Mexican Forms of Certhia. 



Auk 

 Oct. 



ground immediately surrounding it, generally looks as though 

 bespattered with whitewash, from the excrement of the bird, 

 which lives entirely on fish. The eggs, from four to six in 

 number, are small, and have a thick, soft, calcareous shell, bluish- 

 white when first laid, but soon becoming discolored. The young 

 are hatched blind, and covered with an inky black skin. They 

 remain for some time in the squab-condition, and are then highly 

 esteemed for food by the northern islanders, their flesh being said 

 to taste as well as a roasted hare's. Their first plumage is of 

 a sombre brownish-black above, and more or less white beneath. 

 They take two or three years to assume the fully adult dress, 

 which is deep black, glossed above with bronze, and varied in the 

 breeding-season with white on the cheeks and flanks, besides 

 being adorned by filamentary feathers on the head, and further 

 set off by a bright yellow gape. The old Cormorant looks as 

 big as a goose, but is really much smaller ; its flesh is quite 

 uneatable." (Pt. I, p. 105, Cormorant.') 



It will be noticed, that Mr. Ridgway says the Cormorants, 

 speaking generally of the family, lay from two to five eggs, while 

 Professor Newton in the above account says from four to six. 

 When I printed my ' Comparative Oology of North American 

 Birds,' I had apparently overlooked this discrepancy in the two 

 authorities just quoted. In Professor Collett's photograph the 

 clutches of the nests in sight are evidently three to five each, but 

 the number in the set here may have been influenced by the 

 birds having been so often interfered with, and their nests so 

 frequently robbed. 



CRITICAL REMARKS ON THE MEXICAN FORMS OF 

 THE GENUS CERTHIA. 



BY HARRY C. OBERHOLSER. 



That there exist in Mexico two well defined races of the genus 

 Certhia appears to have been first recognized by Count Hans von 

 Berlepsch. He, in 1888, described x a new subspecies of the 



'Auk V, 1S88, 450. 



