Scientists are setting out to solve the mystery of where rockhopper penguins that breed in New Zealand's sub-Antarctic islands disappear to each winter.
The small crested birds leave Campbell Island in April and return to breed in October.
National Institute of Water and Atmospheric Research scientists, helped by funding from National Geographic, will attach tracking tags to 88 penguins.
NIWA scientist Paul Fagar says the species has been declining and it would be good to discover the reason and be able to put in place management practices to slow that.
The tracking tags will be retrieved after the breeding season in October next year.