Status of Gould’s Petrel Pterodroma leucoptera caledonica in New Caledonia: distribution, breeding biology, threats and conservation

ABSTRACT

Pterodroma leucoptera caledonica is a subspecies of Gould’s Petrel endemic to New Caledonia. Its distribution, abundance and breeding biology are poorly known. Extensive surveys of New Caledonia between 1994 and 2014 located only two breeding colonies, and a further likely, but still unconfirmed; the total estimated size of the population could be of the order of 5000–7000 breeding pairs. Nesting burrows were situated either near streams or on slopes near ridges. The breeding phenology of caledonica was similar to that of the Australian leucoptera, but with a breeding calendar that lagged that of leucoptera by 2–4 weeks depending on year and breeding parameter. Breeding success was low, with evidence of a high level of predation of eggs, chicks and adults by rats, pigs and cats. Pigs also destroyed nesting burrows. Permanent bait stations installed to control rats at one colony appeared successful, but the control of pigs and cats is much more problematic. If, as expected, the level of predation observed at one colony extends across all breeding colonies, population decline is inevitable and extinction likely in the long term. With no populations of P. l. caledonica on predator-free offshore islands, translocation to such sites may be evaluated to safeguard this subspecies. In the meantime, we recommend that the global status of Gould’s Petrel Pterodroma leucoptera be upgraded from Vulnerable to Endangered.

KEYWORDS:

• New Caledonian Petrel
• breeding
• conservation
• predation
• Black Rat
• Gould’s Petrel

Acknowledgements

We thank the Department of Natural Resources from New Caledonia for funding this study, especially M. Pandolfi, and also the Cumberland Bird Observers Club for their support. CNRT funded partially V. Bretagnolle and the Société Calédonienne d’Ornithologie. We also thank M. Blanc, F. Bierly, P. Brun, J-M. Fabre, A. Guillemont, J-M. Mériot, L. O’Neill, C. Pegaz and C. Sorin for logistical help, but particularly I. Brun and J. Broudissou for sharing many nights prospecting for colonies. B. Eliotout, F. Hannecart, G. Hunt, J. Baudat and B. Leroy provided information; Y. Cherel identified prey items; and S. Dano did molecular sexing. HS also express his thanks to François and Gabriel Levionnois for supporting pelagic works during January–March 2020. Finally, F. Cugny at SCO helped with logistics and administrative aspects, and S. Gaba and L. Demay helped very much with statistical outputs.

Disclosure statement

No potential conflict of interest was reported by the author(s).