Common tern

Sterna Hirundo

The common tern is a silvery-grey and white bird with a forked tail and a distinctive summertime black tip to its orange-red bill.  Hirundo – the second half of its scientific name – is the Latin word for swallow and indeed these graceful birds are often referred to as sea swallows.

Experts at catching fish, common terns can often be seen hovering above the sea, head down, intently searching for prey in the water.  They plunge-dive and their long, pointed bill acts like a spear.

Common terns arrive in the UK from early April, flying here mainly from West Africa, although a few spend the colder months in Spain. They’ll head back south at the end of the summer, in August or September. First year birds stay in West Africa for the summer: common terns don’t breed until they’re 3 or 4 years old.

All about common terns

Common terns are often confused with the Arctic tern at a distance and, as a result, some bright spark had the idea that the two species should be collectively referred to as a ‘Commic’ terns.

Common terns measure between 34-37 cm in length with a wingspan of 70-80 cm. They have grey upperparts and white underparts, complemented by a long neck and a dark cap on their heads. A distinctive dark ‘wedge’ can be seen in their outer primary feathers. In flight, their wings appear silvery grey underneath. Their wings are a little broader compared to those of Arctic terns. The common tern has shorter tail streamers than other terns and deep red legs.

With a distinctive shrill kyar-kyar-kyar call you’ll likely hear a colony of common terns before you see them.

Feeding

You’ll sometimes see a common tern carrying a fish crossways in their bill. This might be to feed to their young or a male bird with a courtship offering to a female mate. Their diet mainly consists of small fish such as sand eels and sprats.

Breeding

Common terns lay 2-3 eggs in May, with both male and female birds taking part in the incubation which lasts around 22 days. The young leave the nest after 3-4 days to hide in nearby vegetation and wait to be fed. Chicks typically fledge by 28 days after hatching and become fully independent at 2-3 months. Instead of building a traditional nest, common terns create a small depression in the shingle or sand, with both adults contributing to the nest construction. They nest in colonies and readily use artificial rafts, and they are also known to nest inland.

Local spotlight

Over recent years floating platforms known as ‘tern rafts’ have been a useful way of providing a safe habitat for breeding common terns by alleviating the problem of fluctuating water levels.  Several nature reserves around the Solent have benefited from this initiative.

Conservation status

Due to localised breeding and their vulnerability to predation and storm surges, common terns are classified in the UK as Amber, that is, a species of concern.

Common terns are a qualifying feature for the Solent and Southampton Water Special Protection Area and the Chichester and Langstone Harbour Special Protection Area – that means, when the sites were designated, a nationally significant number of the species used the areas.