SANDWICH TERNS: NO LINK TO BREAD SLICES, SAY SCIENTISTS

Have you noticed how newspapers and periodicals increasingly seize every opportunity for a headline ending “…say Scientists”. It lends a spurious authority to any tenuous assertion, like “astronauts unlikely to find cheese on moon, say Scientists” (suggesting at least the faint possibility of some mature cheddar lodged in a crater). Or “Frooty-pops cereal may protect against ingrown toenails, say Scientists”.  To which the proper response is: “research reference please”. But it seems 37.9% of people are actually prepared to believe this tendencious stuff… say Scientists.

But I digress. To the business in hand. The Sandwich Tern (Thalasseus sandvicensis) is a smart-looking medium-sized tern. Its clearest ID signifier among terns is a sharp black beak with a yellow tip. Also, its black legs helpfully distinguish it from other tern species that have orange legs.

The origin of the name for this species is an unexpected one. The Thaleasseus (formerly Sterna) simply refers to the sea (Gk). The Sandwich part is more complicated. It’s certainly nothing to do with a tasty filling for a sliced bread snack **. Other bird species such as Branta sandvicensis, an endemic Hawaiian goose, have the name because Hawaii was historically known as the Sandwich Islands. But Sandwich terns are not found there. In fact, the name comes from the town name of Sandwich, Kent UK (sand wic OE – ‘trading post by the sea’). The ornithologist who first described the bird in 1787, John Latham, just happened to live there. (And how fortunate for ornithology that he did not come from Pratts Bottom, also in Kent).

Sandwich terns have a wide range around the world. As the range map below show, the most significant breeding area is Great Britain and northern Europe. On Abaco, the birds are uncommon summer residents. Both images above were taken on the main island, the top one at Sandy Point on the jetty (an excellent place for birdwatching, incidentally).

Like all the Thalasseus terns, the Sandwich tern plunge-dives for fish. I love the sight of diving terns. They hang high in the air as they scope out the water for fish, only to break free from the sky and smash down into the sea, often emerging with a silver prize. Here’s a wonderful photo of one that missed its meal – and one that succeeded.

 An endearing characteristic of these terns can be seen during their courtship display. The male will catch a fish, then offer it to the female. Her acceptance of the gift signals her readiness to approve the male as a suitable mate. 

Of the  12 tern species recorded for Abaco most are summer residents, some of which breed on Abaco. The royals are the only permanent residents; and the Forster’s are the only winter residents. The other 4 species are transient in migration, or vagrant (arctic tern).

As I have mentioned before, a very good source for easy ID to distinguish between different birds of the same family is to head off to BIRDORABLE. The drawings (cartoons!) may not be scientific, but they do highlight the most notable distinctions. Invaluable as a last resort. Or first resort, even! For similar-looking birds, compare the beaks and the legs. The composite below shows how simple it is.

Noisy neighbours? Put this short recording of a sandwich tern colony in the breeding season on a continous loop, and you have the makings of a powerful retaliatory weapon. They’ll be out within a fortnight…

Alex Lees / Xeno-Canto

** The food we call a sandwich was named after the 4th Earl of Sandwich. He found eating while playing cards inconvenient, so asked his valet for two slices of bread, requesting “and squash a tern between them, if you’d be so very kind…” The Sandwich Islands were also named after his Lordship by Captain James Cook, as a compliment for financially supporting an expedition there, say Historians…

Credits: Danny Sauvageau (1, 4, 5); Bruce Hallet (2); Woody Bracey (3); Ken Billington (6); Alex Lees @ Xeno-Canto, Birdorable, wiki for range map & info, other magpie pickings of glistening facts