Puffins lay one egg that is incubated in turn by each adult for approximately 39-43 days (about six weeks!). After the egg hatches, the chick—called a puffling—stays in the burrow and awaits food from its parents. The puffling grows to full size in about six weeks and then flies away from the island to spend its next three to four years floating on the high seas.
This adult Atlantic Puffin is returning to its burrow with fish for its chick. Both the male and female puffin take turns bringing fish. The adults feed the chick fish for approximately 45 days, although that period may be considerably longer depending on the quality of the fishing resources nearby, after which time the puffling is large enough to fledge (leave) the nest.