372 SNODGRASS AND HELLER 



and Narboro specimens, and specimens may be selected from each set 

 having almost no distinguishing mark whatever between them. This is 

 very evidently a case of convergent evolution, for the general tone of 

 coloration of the upper parts of the Albemarle-Narboro birds is brown, 

 resembling that of the James and Indefatigable specimens, while that 

 of the Bindloe specimens is dusky, resembling that of the Abingdon, 

 Tower and Culpepper specimens. 



The collection contains five adult males and six adult females taken 

 at Tagus Cove, Albemarle, during January and March ; two adult 

 males and one adult female taken at Iguana Cove, Albemarle, the last 

 of December; six adult males and five adult females taken at Eliza- 

 beth Bay, Albemarle, in February ; and seven adult males and eight 

 adult females from the east and north sides of Narboro Island in Jan- 

 uary, March and April. Besides these we have numerous immature 

 birds. 



