Wednesday, 15 April 2020

T is for Terns

Please remember! We ask that people do not visit the Reserve particularly if you have to travel. All car parks on Holy Island are closed to visitors until government restrictions are lifted. Many residents on Holy island fall into the vulnerable category. Please adhere to these guidelines for the health and safety of yourself and others during this time.
With Terns now arriving back in the UK for the breeding season T could only be for Terns. Sandwich Terns can now be heard along the coast and it won’t be long until the rest of the cast of the British breeding Terns make themselves known up and down the coasts of the country.
Terns account for around 40 species of bird across the world, and with their aerodynamic wings and forked tail, are regarded as masters of flight. With their incredible aerial ability, Terns make some of the longest migrations known in the animal kingdom. It was due to their body shape and seasonal migration, harking the beginning of summer, that they earned the nickname ‘Sea Swallows’, a term coined in the UK in the early 17th century.
The Terns that this phase describes will be one of 5 UK breeding species which are Arctic Tern, Common Tern, Sandwich Tern, Roseate Tern and Little Tern. Each of these birds have different migration strategies but all of these species can be found at Lindisfarne National Nature Reserve during the summer months. The Reserve is a breeding ground for Arctic, Common and Little Tern but is also an incredibly important pre and post breeding roosting site for Sandwich and Roseate Terns that breed nearby.
Little Tern (Sternula albifrons)
Little Terns are one of the rarest breeding birds in the UK, using sand and shingle substrate to form a small scrape in the ground. Lindisfarne National Nature Reserve supports the 6th most important colony of these amber listed birds in the UK and is monitored and protected from predators and human disturbance throughout the breeding season. Little Terns are Schedule 1 birds which means that it is a criminal offence to disturb their nesting site and only licensed individuals are allowed to enter the colony. Even with this license, we enter the colony only when it is deemed absolutely necessary.
Little Terns courtship feeding
These tiny birds are white all over aside from a black cap and eye mask as well as a yellow bill with a black tip and weigh about the same as a tennis ball. They fly all the way from their West African wintering grounds to breed on the Reserve. With the perfect habitat for nesting and rich feeding grounds nearby it is the perfect site for these birds to set up shop for the summer. Despite the long migration Little Terns live a surprisingly long time with some surpassing their 20th birthday!
Arctic Tern (Sterna paradisaea)
White all over apart from a black cap, blood red bill and small stumpy red legs, Arctic Terns breed in small numbers on Lindisfarne National Nature Reserve and form part of a larger network of breeding sites along the North Northumberland Coast. These incredible birds look so delicate and frail but have one of the longest migrations of any species, wintering of the pack ice of Antarctica! Recent research of GPS tracked birds from the Farne Islands National Nature Reserve show that they fly up to 96,000km in a year, often returning to the exact same spot to breed the following year – a remarkable feat. Breeding in colonies, they become very aggressive toward any intruder, dive-bombing and striking the predator with its sharp red bill, often drawing blood. This proves very effective and has even been observed chasing Polar Bears away from nesting sites in the high Arctic.
Masters of migration - An adult Arctic Tern
What is more incredible is the ability of the chicks, at three weeks old, to fledge the nest and begin the migration to the other side of the planet!
Common Tern (Sterna hirundo)
Despite their name Common Terns are not as numerous as Arctic Terns on terns on the Northumberland coast. They look almost identical to their globetrotting cousins from a far so when being counted they often get grouped together as ‘Comic’ Terns – a mashing together of both their names. The differences are subtle but Common Tern look more elongated in flight, have a long red bill with a distinctive black tip. They also have longer more orange legs, so stand taller than an Arctic Tern. Common Terns travel down to winter in the warm waters off northern and western Africa with a small number returning to the shores Lindisfarne National Nature Reserve each year to breed.
Adult Common Tern - note the black bill tip and longer legs when comparing to an Arctic
Sandwich Tern (Sterna sandvicensis)
The largest of the UK Tern species arrive back to the Northumberland Coast first with the first individuals seen on Lindisfarne National Nature Reserve by early April. They have a black cap that forms a crest and a long black bill with a yellow tip. Whilst they do not breed on the Reserve – the closest breeding ground just a few miles away on the Farne Islands – they use the waters around the Reserve to feed. Their distinctive Ker-rick call can be heard up and down the coast. Lindisfarne NNR provides an important post breeding site for the adults and young to congregate and feed building up fat reserves for the long journey to their wintering grounds in Senegal and The Gambia. They also tend to stay the longest of any of the Tern species with birds seen into November!
Adult Sandwich Terns
Roseate Tern (Sterna dougallii)
The rarest of all the UK Terns is the Roseate Tern with the only colony in England located a few miles south of Lindisfarne, on Coquet Island.   Named for the adult’s rosy, pink hue on their breast this tern has black bill with a red base with bright red legs. The small UK population winter off the tropical waters of West Africa where food is in good supply throughout the winter months. As with Sandwich Tern, Lindisfarne NNR is an incredibly important roosting and feeding ground for these birds post-breeding with almost the entire English population using the site.
Adult Roseate Tern with chicks- they start migration in family parties
Going against what you would think, Tern species breeding on the Northumberland Coast tend to head north before heading south with many birds heading towards the Ythan estuary in Scotland. This is thought to be due to make the shorter overland crossing towards Atlantic Ocean whereby they can follow the European coast down to Africa.
So if you are visiting Lindisfarne National Nature Reserve at any time of year please be aware of breeding and roosting Terns. If you see any protective fencing in the summer, give it plenty of room and if you see groups of roosting birds give them space. Terns migrate unfathomable distances and need to reserve all the energy they can. You can still view and enjoy the spectacle of these birds from a far.

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