Black Petrel

The plumage of the black petrel is all black, as are its legs and bill except for pale sections on the bill. It is a medium-sized petrel: males average about 720 g (25 oz), females around 680 g (24 oz). It has an overall length of 46 cm (18 in) and a wingspan averaging 115 cm (45 in).

It is endemic to New Zealand. It was previously found throughout the North Island and Northwest Nelson in the South Island, but predators (feral cats, pigs) caused their extinction on the mainland from about the 1950s. It is often seen in the outer Hauraki Gulf from October to May. Breeding is now restricted to the main colony on Great Barrier Island (c. 5000 birds over summer, including approximately 1300 breeding pairs and 1000 "pre-breeders" seeking mates) and a small colony of c. 250 birds on Little Barrier Island. In addition to breeding birds, there are likely to be a further 6000 juveniles, pre-breeders and non-breeding birds at sea. Black petrels may range from the east coast of Australia all the way to the coast of South America between Mexico and Peru and the Galapagos islands. Females and males forage separately and in different places – it is not known why. Birds forage much closer to the Hauraki Gulf over the summer and autumn while incubating an egg and raising a chick – mainly in the Tasman Sea and to the north-east of New Zealand.

They may feed at night or during the day (unlike albatrosses which do not feed at night). Birds will aggressively follow fishing boats and longline hooks and may dive up to 20m below the surface after baits. Black petrels can cover amazing distances – the longest recorded foraging trip for a bird from Great Barrier Island is 39 days. Mapping of foraging patterns against fishing activity in New Zealand waters is underway.