82Wildlife Conservation Plan for Seabirds

82 Wildlife Conservation Plan for Seabirds

Fluttering Shearwater (Puffinus gavia)

TABLE Species information for the Fluttering Shearwater (Puffinus gavia)

Image unavailable in extracted textLife History and Distribution

The Fluttering Shearwater (Puffinus gavia) is a small slender-billed shearwater with dark brown upperparts and white underparts. The species is similar in size, shape and appearance to Hutton’s Shearwater (P. huttoni). This species is a common and widespread species endemic to New Zealand. This species breeds on small, vegetated islands and rock stacks. It nests in colonies in burrows under grass, scrub or coastal forest, but occasionally breeds in rocky cavities (Marchant and Higgins 1990).

The largest colonies are found in the Three Kings group, Moturoa group, Motuharakeke (Cavalli Islands), north-west Chickens, Bream Islands, Mokohinau group, Channel Island, Mercury group, Ruamahuanui (Aldermen group) and Trio Islands, as well as on several other islands in the Cook Strait. The breeding biology of the species is poorly known but laying of eggs is believed to begin in early September, chicks fledge from late January (Powlesland and Rickard 1992). Fledglings, and possibly some adults, move towards the east and south of Australia in February, but most remain near to breeding colonies throughout the year (Marchant and Higgins 1990, Powlesland and Rickard 1992). Birds feed mostly on fish and some coastal krill (Marchant and Higgins 1990).

Brooke (2004) estimated the global population to number at least 100,000 individuals. The population is suspected to be in decline owing to predation by invasive species.

Historically, the species has been extirpated from several breeding locations by introduced feral cats (Felis catus), Black Rats (Rattus rattus) and Brown Rats (R. norvegicus). Invasive rats have now been successfully removed from considerable parts of the breeding range, yet they are still present at some sites and likely to have a negative impact on breeding success. At present, the species survives mostly on islands free of introduced mammals, but some persist in coexistence with populations of Polynesian Rat (R. exulans) and Black Rat (Saddle Island). These populations are relatively small, and the rats may be having a significant effect on breeding success. There is a future risk of re-invasion on currently predator-free islands. Other potential threats include overharvesting of inshore prey stocks, bycatch in fisheries. Fluttering Shearwaters are frequently trapped in fishing gear in inshore waters, with unknown impacts on the global population.

Wildlife Conservation Plan for Seabirds 83

Hutton’s Shearwater (Puffinus huttoni)

TABLE Species information for the Hutton's Shearwater (Puffinus huttoni)