Wednesday 17th February comments: Over the last week we’ve been focussing on the snow and weather which has hit the east coast, including the Isle of May, hard. We will know over the next few weeks what damage, if any, this has caused to our breeding seabirds but until then we’ll delve back into our seabird series which we were featuring seabirds of the Isle of May. Today we feature our second Tern species as we introduce the Common Tern.
Common Terns are distinctive birds as they are light grey upperparts, white underparts, a black cap, orange-red legs and a narrow pointed bill which is generally red with a black tip to the end. The Common Tern has a circumpolar distribution and it has four subspecies which breed in temperate and subarctic regions of the world. The species is a strong flyer as they winter in the southern hemisphere (but more on that in another blog soon)
Common Terns breed in a variety of habitats but generally flat, poorly vegetated surfaces which are close to water and can adapt to artificial floating rafts. They nest both in coastal waters and inland freshwater. On the Isle of May the first birds return in late April and aerial courtship displays soon follow above the island. The majority of birds nest on the Tern Terraces by the Beacon and by the third week of the May, the first eggs are laid and the nest site is usually a small scrape in shingle or gravel. The species can lay up to three eggs (rarely four) and the clutch is incubated by both parents and will hatch after 21-22 days. Once the chicks hatch, they are cared for by their parents and will take to the wing after 22-28 days (which is usually mid-July on the island). Like most terns, this species feeds by plunge-diving for fish but molluscs, crustaceans and other invertebrate can make up their varied diets. Following the breeding season, family parties will disperse the island in August and begin the long journey south to their wintering grounds.
However more on the species in the forthcoming days as these birds are not as common as their name suggests and we’ll reveal how many nest on the Isle of May! Stay tuned.