37. Chatham Island Petrel
(Pterodroma hypoleuca axillaris)
Plate 16

Field Characters: 53/31. A small, dark-grey and white gadfly petrel with conspicuous underwing pattern. Crown, eye patch and nape greyish black, the dark feathering extending over the sides of the neck to form an incomplete collar. Mantle and uppertail coverts grey, tail darker. Upperwing brownish black. Underbody, including undertail coverts, white. Underwing white, with well defined black leading margin extending in a broad black bar diagonally from the carpal joint over the inner underwing coverts and merging with the black axillaries.

Bill black; feet fleshy coloured, with black extremities.

Differs from all other Cookilarias by the broadness and extent of its striking underwing pattern, and black axillaries.

Flight not recorded, but presumably as for other small gadfly petrels. Does not follow ships.

Late summer breeder at the Chatham Islands, and has not been observed away from its breeding grounds.