New Zealand albatross birds are just like humans - they take long winter holidays to warmer parts of the world thousands of kilometres away, scientists have found.
The native Campbell albatross and the Grey-headed albatross have been tagged and tracked by the National Institute of Water and Atmospheric Research (Niwa) for three years.
They found that the Grey-headed albatross travels 7000km - from Campbell Island to South Australia and onto the Indian Ocean further to the west, not as far as expected.
After finishing breeding, the Campbell albatross travels to South Australia for four months before returning to Campbell Island, 600km south-east of Stewart Island.
The Campbell albatross breeds on Campbell Island only, but the Grey-headed albatross breeds elsewhere, said Niwa scientist David Thompson.
The number of Grey-headed albatross was thought to be declining, but the Campbell albatross population - which has declined in previous decades - was thought to be stabilising or even increasing slightly, Dr Thompson said.
Both species are classified as vulnerable.
Scientists are half-way through the six-year project.