One of our most exciting endeavors on this lovely seabird island is monitoring the Alcid burrows around the perimeter of the island. Alcidae is a family of seabirds that includes Atlantic Puffins, Razorbills, and Black Guillemots, all of which breed here on Petit Manan. Unlike the terns that lay their eggs on the exposed ground, each of these species raise their chicks in a protective burrow. Razorbills and puffins always have one egg, while guillemots often have two.
Usually burrows are in the crevices between the pink granite rocks that border the island, but sometimes our Alcids choose some unconventional sites, like in the foundation of a fallen building, or under the boardwalk that stretches the length of the island from the boathouse to the lighthouse. In addition to rock burrows, puffins are able to dig burrows in the sod that can be over 6 feet long! Because Petit Manan is a tiny island with an incredible number of breeding birds, we also provide artificial burrows made from wooden boxes or overturned plastic buckets with tubes attached to the entrance so that the birds can crawl into a protected space like they would in their granite or sod burrows.
Alcids establish burrows in early May, around the time we arrive on the island. At the beginning of the season, once the birds have laid eggs, we do a survey of the burrows to determine which ones are active, peering in but trying not to disturb the birds while they are incubating. Later in the season (now!), once most of the chicks have hatched, we do another thorough investigation during which we “grub” the puffin, guillemot, and razorbill chicks and adults.
We remove them from their burrows so that we can put small metal identification bands around their legs, each with unique number/letter combination so that we can resight individuals later and determine how often they return to the island and what other locations they might be visiting year-to-year. We also weigh chicks now and again at the end of the season to monitor their growth. Many of the puffin and guillemot chicks won’t fledge until after we’ve left the island in the middle of August.
“Grubbing” an Alcid can be quite a surprising experience, as it often involves reaching blindly into a dark, slimy crevice and feeling around until you find a fluffy little chick… or until your fingers meet the sharp vice grip of an adult puffin’s powerful bill!
So far this season we’ve noticed that the number of breeding guillemots on the island is on the rise, but there seem to be fewer breeding puffins this year than in years past. We have one confirmed Razorbill chick, and two more possible sites. We’ll keep you posted as we collect and analyze more data about our awesome Alcids!