Ranguru
The Chatham petrel (Pterodroma axillaris ) or ranguru (Maori) is a medium-sized, grey, white and black gadfly petrel. It only breeds on the Chatham Islands, New Zealand, and until recently was restricted to the 218-hectare Rangatira or South-East Island.
The Chatham petrel is a medium-sized petrel with a mottled dark-grey and white forehead, dark grey back and upper wings, and white underparts. A black diagonal bar extends from the leading edge of underwing to a black ‘armpit’. The shoulders and upper-wing coverts are a deeper grey giving a dark M pattern across the spread upper wings.
The bill is black and strongly hooked tip. The eye is dark, and the legs and feet are pink, with dark outer toes and webs. The sexes are alike.
Chatham petrels are rarely observed away from the colony; the few at-sea records are from ships in oceanic waters.
Chatham petrels nest in burrows under the forest canopy to which they are generally faithful to over time. Leaves are used as nesting material. Each pair lays a single white egg in December or January and the chicks fledge in May or June.
The population is estimated at 2,000 birds and is classified as nationally vulnerable. Present throughout the Chatham group before the arrival of man, predation by man and introduced mammals (rats and cats) and the loss of forest habitat saw the species restricted to Rangatira island. Before conservation efforts began, the size of the Rangatira population was limited by burrow competition with the broad-billed prion Pachyptila vittata, of which an estimated 330,000 pairs inhabit the island.
