On one island off the coast of Pembrokeshire an endangered bird is making a comeback.
While the numbers of puffins in most parts of Europe are dwindling, the population on Skomer is booming.
Now scientists are trying to find out why they are doing so well, and if the island could be key to saving the colourful birds.
Researchers have attached tiny GPS tracking devices and cameras to the seabirds to find out where they go to get their food, how they catch it and exactly what they are eating.
“Some of them will go 75km and back again in a day,” said Dr Annette Fayet.
“That is 150km in a day, for a little puffin, that’s quite a lot.”