Roseate terns at Coquet Island

Common Tern

Common terns (Sterna hirundo) have similar shape and build to roseate terns with a black cap on head, with a longer neck and darker grey mantle and white underparts. However, the key difference between the two is that common terns have longer orange-red legs, shorter white tail streamers and long orange-red bill with a black tip.

Common terns, unlike roseates, have a less restricted breeding range and can also be seen inland nesting on large lakes. They have readily adapted to use artificial substrates for nesting, including floating rafts. Like all other breeding terns in the UK and Ireland, common terns are also migratory, wintering on the west coast of Africa.

Photo by Paul Morrison

Roseate Tern

The roseate tern (Sterna dougallii) is the rarest breeding seabird in the UK & Republic of Ireland. Historically, because of their beautiful plumage, these rare birds were hunted almost to extinction in Britain during the hat-making craze. Today, there are only three small colonies supporting just over 1850 pairs (2016).

Adult roseate terns have a black cap and extremely pale body plumage, with light grey back 'mantle' and creamy-white underparts with a faint rosy tinge to the breast (not always easy to discern). An important distinction is that their bill is all black in May, then usually becomes red at the base and is half red by August. This, along with their very long white flexible tail-streamers and characteristic voice, helps in distinguishing these terns from the others.

Roseate terns undertake an amazing journey each autumn down the European coast to the west coast of Africa, returning to British Isles in April.

Photo by Brian Burke

Puffin

The Atlantic puffin (Fratercula arctica) is a small seabird with black upperparts and white underbelly. During the breeding season, they have a parrot like multi-coloured bill (orange, yellow and blue), a large white patch on its face and bright orange legs.

Puffins spend most of their life at sea and are only found on land during the breeding season (between April and early August), making them a true seabird. Unlike terns, puffins have to constantly flap their wings when flying, however to catch their fish, they can swim well underwater using their wings to steer. Puffins nest in colonies in burrows or sometimes in boulder screes to hide from predators. They dig their burrows using their bills and push dirt out behind them with their feet. Puffins are very site faithful and return to reuse their burrow in following years.

Photo by Wez Davies

Habitat management

Prior to the breeding season, the wardens repair the tern terraces which may have been damaged in the winter storms. The terraces are resurfaced with shingle collected from the island foreshore to reduce vegetation growth. Nesting plots of common terns are cleared of vegetation, strimmed and mown to a low sward.

Although a little bit of vegetation is good for chicks to hide from predators, controlling the vegetation is essential as too dense sward will reduce the space available for terns to nest and prevent puffins accessing their burrows. There is a lot of competition for nesting space on an island with thousands of breeding seabirds! In addition, the eggs and chicks can get smothered by dense vegetation, which inhibits their ability to keep warm, especially when it is cold and after rainfall.

Photo by Paul Morrison

Lighthouse / Monastery

Not only are some of these islands important for breeding roseate terns; they also have an interesting history, such as Coquet Island in Northumberland with remains of an early monastery from the 7th century. During the 12th century, the monastery was home to a hermit called St Henry.

In addition, Coquet Lighthouse was built in 1841 and apparently the first lighthouse keeper was William Darling, the elder brother of Grace Darling (famous lighthouse keeper who helped rescue survivors from a shipwrecked paddlesteamer). The lighthouse is now automatic, however prior to the early 20th century, the lighthouse on Coquet used to be inhabited by three lighthouse keepers and their families.

Photo by Wez Davies

Night watch

There is a 24-hour wardening system in place on Coquet Island to protect roseate terns from egg collectors sneaking in under the cover of darkness and taking their eggs. Despite this is illegal, unfortunately there are still incidents involving people desperate to steal and add a rare bird's egg to their collections. Terns are known to be susceptible to disturbance, which can cause the abandonment of their nests and shrinking of the colony size in subsequent seasons.

Roseate terns usually only lay two eggs (unlike for example, blue tits which can have up to 12 eggs) and the theft of those eggs usually means the end of the breeding season for that pair. They will have to try again the following year, if they survive the journey travelling to and from Africa. The roseate tern is the rarest breeding seabird in the UK and Ireland and we need every egg to hatch in hopes to restore their breeding population.

Photo by Wez Davies

Warden's Accommodation

The island is inhabited by a team of wardens who monitor the seabirds during the breeding season. Although working with wildlife is an amazing opportunity, it is not an easy job working on a remote island for months with limited drinking water supplies and facilities. Provisions are brought out from the mainland by a boat and some need to always to be stored away as emergency rations on the occasions when crossing is not possible due to bad weather. Wardens need to watch not to bring any invasive species of plants and animals. Like rats, invasive plants can be very difficult to remove, once they are established.

The accommodation has a small kitchen, a couple of bedrooms and a small office where the monitoring data are computerised. Electricity comes from solar panels and water for washing and laundry come from desalination unit.

Photo by Wez Davies

Monitoring

The wardens are also tasked with the monitoring of key species breeding on the island. By counting the number of nesting pairs, eggs and successfully fledged chicks, we can garner whether the breeding population is doing well on the island.

This includes recording information that can affect the breeding success, particularly predation, weather and diet.

Ringing and subsequently ring reading (using telescopes and binoculars) are also undertaken on every roseate tern site, allowing wardens to gain a better idea of their movements between sites, survival rates and longevity (the oldest recorded roseate tern is 25 years).

Wardens monitor how often parents bring food back to their chicks, along with the type of prey and its size. Unlike sandeel and sprat, some fish species (e.g. pipefish) may not supply the chicks with the necessary energy requirements. In addition, if the size of fish is small or there is less food being brought in, it will likely have a negative impact on the chick's condition and eventual survival.

Photo by Paul Morrison / Wez Davies

Video compilation by Brian Burke

Roseate Tern Terraces

Unlike the other four tern species (Sandwich, common, little and Arctic) which breed in the UK and Republic of Ireland, roseate terns prefer to nest in sheltered locations, like crevices between rocks, amongst taller vegetation or behind beach debris on shingle. Terns make a slight scrape (shallow depression) in the ground and their eggs are camouflaged which helps hiding them from any eager predator.

To counter the lack of available nesting habitat, wardens started artificially creating areas for the roseate tern to nest. These purpose-built tiered terraces increase the space available for numerous nest boxes for the terns to use. Roseate terns have adapted to this assistance and have readily started nesting in boxes, which have significantly improved their chances of breeding success by protecting the chicks from bad weather and predation from large gulls.

Photo by Paul Morrison

Video compilation by Wez Davies

Mixed Tern Colony

Roseate terns breed together with other tern species, particularly common and Arctic terns. Roseate terns are less defensive of their nests and young in comparison to common terns and they often rely on the surrounding tern colony to defend them from predation.

Predation of eggs, chicks and adults affects the breeding success of roseate terns and it can prevent terns from establishing new colonies or cause the abandonment of active nesting sites. Avian predators include crows, raptors and large gull species. Mammal predators near mainland include foxes, mink and stoats. On isolated islands like Coquet, it could be rats which have been known to decimate seabird colonies. Avian predators include crows, raptors and large gull species.

The Roseate Tern LIFE Recovery Project aims to restore historical sites where roseate terns used to nest. Through improving site conditions for common tern colonies, roseate terns might be more likely to recolonize these sites in the future.

Photo by Brian Burke

Bird Sanctuary

All wild birds are protected by law in some form, but some species are afforded additional protection during their breeding season, including their nests, eggs and dependent young (Schedule 1 species of the UK's Wildlife and Countryside Act 1981). Roseate terns are of high conservation concern and are listed on the national Red List in the UK and Amber List in Ireland.

Islands support not only roseate terns, but also thousands of other breeding seabirds, and therefore they are designated as European Special Protection Areas. These sites are protected all year round to safeguard the fragile habitat and to avoid disturbing the birds during the nesting period. This means that trespassing on these islands is not allowed. The Atlantic puffin has recently been added to the IUCN (International Union for Conservation of Nature) Red list of birds facing global extinction as “Vulnerable”, following dramatic declines in their numbers over recent years.

Photo by Wez Davies

Tern Diet

Terns feed mainly by snatching food from the sea surface or by plunge-diving up to one meter in depth. Most smaller tern species have relatively short foraging ranges of up to 10 km and their diet is predominantly made up of sandeels and sprat. This makes terns more vulnerable to extreme weather conditions and local food shortages compared to species with greater foraging ranges and better ability to dive (for example gannets).

Unfortunately, climate change is causing the sea temperature to rise, which disturbs this delicate marine ecosystem and food chain. As a result, sandeels are facing lower reproductive potential with their main food source, zooplankton species Calanus finmarchicus, becoming scarcer and the decreasing availability of their own overwintering habitat conditions due to the reduced amount of oxygen in the substrate. This affects the stock size and energetic content of sandeel available to top predators such as seabirds.

Photo by Brian Burke

Tourism / Sight-seeing

As the roseate tern colony is protected by a status of 'Bird Sanctuary', visitors are unable to land on the island. There are however boat trips which are a fantastic solution for tourists to enjoy the spectacular views without causing disturbance to the breeding birds. On occasion, dolphins and seals have been seen from the boat as well!

In 2016, the first ever roseate tern LIVE webcam was set up for visitors to see these rare nesting birds raising fluffy little chicks directly from their phones and laptops! To watch the LIVE spectacle, click on this link: www.rspb.org.uk/coquetlive (between May and August).

Photo by Brian Burke

Video compilation by Wez Davies