Sandwich tern

The sandwich tern (Sterna sandvicensis) takes its name from the town of Sandwich in Kent (south-east England); it does not eat sandwiches! (The town and the snack are connected in a roundabout way, but that’s another story!)

The sandwich tern is one of the larger terns, being about twice the size of the little tern. Although similar in appearance to several other tern species, such as the arctic tern and common tern, its most distinctive feature is the shaggy crest on the nape of the neck.

The sandwich tern is widespread in Europe and parts of North and Central America. Most European populations migrate to Africa for the winter, flying as far as South Africa. Some birds winter in the Persian Gulf. The sandwich tern is a coastal bird, only rarely straying inland.

Appearance

Male and female sandwich terns are very similar in appearance, being about 40 centimetres (15.5 inches) long. The bird has long thin wings, a forked tail, and a slender black bill with a yellow tip. The legs are black.

The plumage is light in colour, being almost white on most of the body, which makes the black cap and nape crest stand out all the more. There is grey colouring on the upper body and wings, the latter being dark-tipped. In its winter plumage the sandwich tern loses some, but not all, of its black head feathers.

Behaviour

The sandwich tern is a strong flyer that can also hover. It feeds by plunging from considerable heights. It has a loud and shrill grating “seabird” call.

Breeding

The sandwich tern returns to its breeding grounds in late March, seeking a coastal nesting site that can be on sand, shingle or rocks, although locations with at least a little grass cover are preferred. The male sandwich tern performs a courtship display for the female which involves the offering and accepting of a fish. Sandwich terns nest in dense colonies, which can number up to a thousand pairs. These colonies are, not surprisingly, extremely noisy places!

The nest is little more than a scrape in the ground, lined sparingly with plant material. The usual clutch is two eggs, although sometimes it is only one and sometimes three. These are laid in May or early June and both partners incubate them for up to 24 days. Only one brood will be raised. The young stay in the nest for 6 or 7 days, sometimes longer, after which they wander away, soon forming flocks with other young birds. They are able to fly from about 35 days after hatching.

As mentioned above, the sandwich tern dives for its food, which comprises sand eels, mackerel, whiting, or whatever else is available locally. Sandwich terns will also eat molluscs, crustaceans and worms.

Sandwich terns leave for their winter quarters in September.

Conservation

The sandwich tern has amber conservation status in the UK due to constant threats to its habitat. Were it not for the regular breeding colonies at coastal nature reserves in eastern England, it is probable that this species would be in serious trouble in terms of survival in Great Britain.

© John Welford