White-vented Storm-Petrel (Oceanites gracilis)

Monotypic

Two subspecies recognized:
O. g. gracilis (Elliot's Storm-petrel) - Unclear, possibly breeds on Chungungo Island off Chile?
O. g. galapagoensis - presumed to be the Galapagos Islands.

Also known as Graceful Storm-petrel
 

Identification

Where and When

Endemic to the Galapagos Islands and Humbolt Current.
 

Photographs on the web

Literature