A species endemic to the Chatham Islands, east of New Zealand. It is a close relative of the Spotted Shag (Stictocarbo punctatus) of the New Zealand main islands. This specimen is a young adult collected in 1925 - in comparison, the breeding adults are fantastic in appearance. Photos can be seen here: Pitt Island shag | New Zealand Birds Online
The bird at the back is a Chatham Island Shag (Leucocarbo onslowi, which is the other species of cormorant endemic to the island group.