Short-tailed shearwater - Puffinus tenuirostris
Photographed off the coast of Kaikoura, New Zealand.
The short-tailed shearwater is probably the most numerous of the world's 37 shearwater species, with an estimated global population of 23 million birds. They breed on islands off southern Australia, mainly in Bass Strait and around Tasmania. Short-tailed shearwaters migrate annually, travelling further north than the related sooty shearwater, from the Aleutian Islands through Bering Strait into the Arctic Ocean. They return across the central Pacific, some migrating south along the west coast of North America. Birds fly around 15,000 km each way, a journey that takes six weeks in both directions. Short-tailed shearwaters are often seen at sea off mainland New Zealand from October to January and in May. Here, they are often mistaken for sooty shearwaters, which are slightly larger, with paler underwings.