The Sandwich Tern is one of three birds to be named after places in Kent, the others are Kentish Plover and Dartford Warbler. Ranger Julie tells us more about these fascinating birds, and no, unlike gulls they don’t eat sandwiches so your picnic is safe!
If you are lucky enough to spot terns then you will witness some of the most elegant and exciting birds to spend time with. The easy part about witnessing their nesting and feeding routines is that, unlike some sea birds, they nest on beaches and scrub land and don’t travel miles and miles away from their nests into open ocean in order to dive for fish.
The Sandwich Tern is a striking bird, larger than the Common Tern it has a tufted punky looking black cap, which really contrasts with the smooth heads of the other terns found on the Kent coast. It also has a black beak with a yellow tip, which is different from the other UK tern species.
The elegant Sandwich Tern with its punk hairdo and yellow tipped beak Photo credit Roy Knight
Whilst the majority of the Bird Wise species, which you’ll find on our ‘Meet the Birds’ page, leave us to breed elsewhere in the summer, the Tern is a bird where we can see the full courtship display, pairing and breeding cycle right on our doorstep. They arrive around the end of March and begin to depart in August, all tend to have disappeared by September. The Sandwich Tern visits exotic climes when it leaves us. Its migration to its over-wintering area takes it to South Africa, India or Sri Lanka. In addition, there is population on the Caspian Sea, between Europe and Asia. These Terns are so well designed that they can quite happily live on fish sources caught from the sea, brackish water and fresh and unusual and useful ability for a ‘sea bird’.
The males begin the breeding season by attempting to present fish, which he lines up across his beak, to a likely mate. Obviously, the more fish he has the better partner he will be as this behaviour is designed to demonstrate that they will be good provider for any resultant offspring. Sandwich Terns are monogamous, focusing on one partner and one nest in a breeding season. Once the female has made her selection, and they have mated, then the bonded pair create a scrape in the soil if inland, or just above the hightide mark on a beach. The beach nesting birds are especially vulnerable to disturbance and predator attacks. Humans and dogs can easily scare the incubating parent off the nest, if this happens and the birds cannot return swiftly to cover the eggs then they cool and the chick will die.
Once the chicks have successfully hatched then the parents take it in turns to travel back and forth from fishing to the nest. You will see them carrying small sand eels, sprats and whiting on regular routes in and out of the colony. The nests are still not safe however as high tides, which coincide when the moon is full can still swamp chicks on the nest. Is it any wonder fledgling terns in Kent are a rare occurrence?
Unfortunately, due to human use of beaches, the Sandwich Tern no longer nests at Sandwich. However, at other important nesting sites you can help by staying off the beach and pulling even further back if your presence appears to be making the terns agitated. In Kent some of the most important tern breeding sites are cordoned off with information signs and boundary markers so that the nests have some peace and quiet and the eggs which are highly camouflaged are not inadvertently destroyed. Do keep well outside these areas and remember it is a prosecutable offence to disturb nesting birds. Tragically, this year one of the largest Sandwich Tern colonies was abandoned due to human disturbance as people landed on one of the islands in the Medway Estuary where they nested.
What’s in a name?
The Sandwich Tern Thalasseus sandvicensis
If we look at its Latin name Thalasseus sandvicensis it contains a whole story about the bird… Thalasseus is from the Greek word for Sea, whilst sandvicensis, translates as Sandwich. No surprises so far – however, normally, a bird with this word as part of its name comes from the islands of Hawaii, which until the 1840s were known as the Sandwich Islands. Our Tern is a Kentish bird for part of its life and so, yes, the names refers to the town in Kent.
For those of you who are very observant about the scientific names of species you might notice that the Sandwich Tern has different family name from the rest of the family of terns. The Sandwiches names begin with Thalasseus whilst all the other terns visiting the UK have Sterna. The idea of using Latin names to clearly differentiate families of animals and birds was developed by Carl Linnaeus (1707 – 1778), a Swedish botanist, zoologist, and physician. Having developed this idea of giving every animal and bird in the world a unique name, shared by no other, he gained the rather snappy title of the ‘father of modern taxonomy’.
The Latin names for individual species are written using a system called ‘binomial nomenclature’. Each animal, bird, plant, organism has a first name, its genus or family, followed by its own individual name. So, Smith John rather than John Smith. Categorising every living thing in the world is a bit of a tall order for a single scientist, so in subsequent years other individuals joined in, once the format of naming was established. In 1787 the ornithologist John Latham formally named the Sandwich Tern ‘Sterna sandvicensis’ after the town where he had observed the Terns, in his county of birth, Kent. However, in 1822 Friedrich Boie, a German scientist decided that as the Sandwich Tern, with its sticky up top knot, should actually be a separate type of tern and gave it the first name Thalasseus.
After a period of calling the Sandwich Tern Thalasseus scientists slipped back into calling it Sterna. However, as late as 2005, when genetic testing was being undertaken on bird DNA, scientists discovered that it was indeed a totally different species of tern, so Thalasseus was brought back into use. Mitochondrial DNA which confirmed the identification of the Sandwich Tern as different from others, is fascinating. This DNA, otherwise known as mtDNA, barely, if at all, changes over time as it comes from the mother directly to the offspring. As a result, the line of breeding of a bird or animal can be traced back dozens and dozens of generations and thousands of years. In this case it confirmed that The Sandwich Tern was a totally different type of tern with a different background to all the other UK terns. So now you know.