Knowing where and how Antarctic penguins, seabirds and marine predators migrate is critical for conservation efforts. Although electronic tracking devices have helped scientists track marine animals’ migration patterns, the devices can be expensive, invasive for the animal and challenging to retrieve. Scientists have discovered a new and potentially better way to track where penguins go over the winter using forensics.
Researchers at the University of Oxford worked in Antarctica with an international team from Louisiana State University, NOAA Southwest Fisheries Science Center, and the Instituto Antártico Argentino. The team attached trackers to 52 adult Chinstrap and Adélie penguins at their breeding colonies.
The team then used the chemical signal of their feeding grounds from tracked individuals to work out where a much larger number of untracked birds had overwintered. These penguins are part of the family of "brush-tailed" penguins named after their approximately 15-inch long, stiff tail feathers which shed after each breeding season and before they migrate to their oceanic wintering grounds.
Dr Tom Hart, a penguinologist in the Department of Zoology at Oxford University, said: ’Knowing where penguins go and what they eat helps us to protect their feeding areas and conserve them throughout the year. The importance of stable isotope tracking is that we can work out where penguins over winter with a single, less disturbing visit to a colony.’
The researchers retrieved data from the birds after breeding season, using a technique called compound-specific stable isotope analysis of amino acids. They then identified the unique chemical signatures of penguin wintering areas, based on the coordinates from the tags and the geochemical signature imprint of the feathers.
Dr Hart added: ’Most marine animals are hard to track, so this approach could be reapplied to whales, flying seabirds and fish. It would even work on dead animals found in nets or on beaches, to help work out where it has come from. So, it could be useful for wider forensics as well as the conservation and management of penguin populations.’
Biology Letters: Stable isotope analyses of feather amino acids identify penguin migration strategies at ocean basin scales