Puffin breeding sites are on coastal areas or islands where the birds dig burrows or tunnels at least one meter deep. They usually keep the same mate for life and use the same burrow for several years, the female laying only a single egg each year. The pair take turns incubating their egg and then feeding and rearing the puffling after it hatches. The young puffin heads out to sea after fledging, living far from land for the next three to five years before returning to its birth place to find its own mate and breed,