Terns are among the most beautiful of our summer visitors. The ones we see on our trips are arctic terns and common terns. They are known as “ the swallows of the sea” and the common tern’s latin name “hirundo” means swallow. There are very subtle differences between these birds and you have to be quite close to notice, the easiest way with binoculars is to look at the beak, the common tern has a black tip to its orange beak but the arctic tern does not, also the arctic tern’s tail is very swallow like with elongated tail streamers.
The common terns migrate to Africa in the autumn and return to the UK in the spring to breed. The Arctic tern is the absolute Olympic champion of migrators having the longest migration of any bird. Incredibly the ones that nest furthest north (in the Arctic) migrate furthest south (the Antartic!) so have almost constant daylight all year round. The furthest round trip is around 50,000 miles, and they do this every year.
The birds that we see will probably not go as far south as the Antarctic perhaps wintering in South Africa leaving Scotland in July to September and arriving back in late April or May.
Terns nest in scrapes on shingle or sand and this makes them very vulnerable to predation. American Mink (released from Mink Farms) have had a devastating effect on colonies of seabirds. In 2001 the Hebridean Mink Project was launched and since then over 17,000 mink have been caught and now there are signs of recovery of species such as Terns. Terns survival also depends on good supplies of fish species such as sandeels and like the puffins requires strong fisheries management to be in place, especially in the North Sea where sandeel decline has been caused by overfishing and possibly climate change. These are really beautiful, inspiring birds and we look forward to welcoming them back in the spring.