New Zealand scientists say they want to try to solve the mystery of the disappearance of a rapidly declining penguin species every winter. Scientists from the National Institute of Water and Atmospheric Research, funded by the U.S.-based National Geographic Society, will travel to the breeding ground of the rockhopper penguin in New Zealand\'s sub-antarctic Campbell Island to attach 88 miniaturized tracking tags to penguins next year. \"We don\'t know where the penguins go during winter,\" NIWA scientist David Thompson said. \"They leave Campbell Island in April, and don\'t reappear until early October,\" he said. \"I suspect they don\'t go too far south, nor are they likely to go too far north. They probably stay at the same latitude, but disperse away from the island, spending that time feeding and regaining condition. \"It could be a crucial stage in the breeding cycle for them. To successfully raise chicks, they need to come back to Campbell Island at the start of the breeding season in good condition,\" he told the Xinhua news agency. From 1942 to 1985, the rockhopper penguin population at Campbell Island declined from about 800,000 breeding pairs to just 51,000 pairs, and the decline has been ongoing since. \"They are unlikely to become extinct in the near future, but this represents a massive decline,\" Thompson said. Diminished food stocks probably caused the falling population, he said. The data from the tagging effort would shed light on the penguins\' winter movements, distribution and habitat use, Thompson said.