Magnificent discovery

Magnificent Petrel can be found close to shore in Vanuatu. Photo: Hadoram Shirihai
Magnificent Petrel can be found close to shore in Vanuatu. Photo: Hadoram Shirihai

A new gadfly petrel subspecies has been described from North Vanuatu, after specimens lay unanalysed in a museum draw for over 80 years, when the bird was observed in the field by Vincent Bretagnolle and Hadoram Shirihai.

The two authors became aware that there might be a new form of Collared Petrel when studying specimens in the American Museum of Natural History. Rollo Beck - discoverer of Beck's Petrel, which was rediscovered in 2003 by Shirihai after it was believed to be extinct - had collected a series of Collared Petrel specimens on the Whitney South Sea Expedition in 1927, including six unusually small and dark birds which stood out as different to the modern authors. Shirihai was then able to photograph some very dark 'Collared Petrels' in 2003, 2006 and 2007 when on pelagic trips to the type location of the new subspecies, east of Mera Lava in the Banks group of islands, in Vanuatu, Melanesia.

This resulted in a special expedition to the islands in December 2009, when the dark form was further observed, and indications of a breeding colony on Vanua Lava were noted, including birds calling from the ground and displaying at night. In common with other recent tubenose discoveries, Magnificent Petrel appears to breed at a different time to some of its local congeners, during the austral spring or summer - birds seen on the expedition appear to have been recently fledged, indicating a hatching two or three months earlier. Adult birds captured had enlarged sex organs in late January strongly suggest a summer breeding season.

The new form appears to be ecologically specialised, mostly attending only the coastal feeding frenzies of terns, boobies and shearwaters, and it is apparently easy to find even on inshore waters, not far from the islands. Magnificent Petrel is smaller than nominate Collared Petrel and appears to only have a dark morph (unlike many of its closely related congeners).

Reference: Bretagnolle, V and Shirihai, H. 2010. A new taxon of Collared Petrel Pterodroma brevipes from the Banks Islands, Vanuatu. Bulletin of the British Ornithologists' Club 130: 286-301.