Things are getting busy on Metinic. Common and arctic tern eggs typically hatch after about three weeks, so we’ve been making preparations before we have an abundance of chicks scurrying around. Based on when the first egg was found, we’re anticipating the first chick to pop out before next weekend. Ahead of hatching, we will conduct a census of the colony, which in turn has several precursors that we have been working on this past week.
As we have two species of terns on the colony, it is important to determine an approximate ratio of these two species. Nests cannot always be reliably told apart without looking at the bird attending. Arctic terns tend to nest higher on rocks and usually only have two eggs, while common terns typically nest in grassy areas between the rocks and will have a complete clutch of three eggs. However, exceptions abound. Perched up in the blinds, we sit and watch as adult terns fly in to their nests. Then we note the locations of a few nests and run down to place a colored flag near the nest: red flags for arctic, blue flags for common. Based on the 152 nests we flagged, it appears that we have a pretty even split, with arctic terns slightly more prevalent.
Another task before the census is the placement of predation nest markers. While we will also be monitoring nests for predation in our productivity plots later in the season, these markers allow us to note egg predation early in the season and outside of the densest parts of the colony. Tongue depressors are painted, and then placed around nests in the colony, denoting the number of eggs in the nest when placed. These will be collected during the census and any nests with fewer eggs than written on the stick will be noted as likely depredated.
Metinic isn’t the only island in the area with breeding seabirds. On Wednesday, we went along with Refuge staff to nearby Two Bush Island. The shrubby vegetation around a small lighthouse serves well to conceal a few eider nests, while some guillemots likely nest in the rocky ledges. On our way back, we circled Crow Island to check on an eagle nest. Two adults were around, but we couldn’t see any eaglets from the boat.
This weekend is the annual Metinic Island sheep shear. We helped to drive most of the sheep from across the island to a corral on the southern end, where they are processed. Watching the shearing in action, it is really amazing how much wool some of these sheep have grown. Hopefully some of that wool will be made into warm layers so that those wearing it can be as cozy as the sheep out here off the coast of Maine.
Until next time!