How the North Wales Wildlife Trust are helping terns at the Cemlyn nature reserve

Sandwich tern with a sand eel

Sandwich tern with a sand eel - Credit: Ben Stammers

Ben Stammers explains how North Wales Wildlife Trust is working to conserve Cemlyn’s precious terns and how you can help


Cemlyn - Credit: Lin Cummings

Even without a huge seabird colony, Cemlyn nature reserve would stand out as a fascinating place. Situated on the rugged north Anglesey coast, a unique, kilometre-long shingle ridge dominates the site, dividing the open water of Cemlyn Bay from a shallow brackish lagoon. The ridge, created by a violent 19th century storm and subtly re-defined by each tide, forms a perfect elliptical sweep and this dynamic landscape and the open, windswept atmosphere catch the imagination of many visitors each year.

In May, June and July every year however, Cemlyn plays host to a phenomenal wildlife spectacle – this popular reserve has become one the best places in the UK to watch breeding terns. Crunching along the shingle, past stands of flowering sea kale and thrift, as a wall of sound builds from the busy colony just over the ridge is a sensory experience in itself at this time of year, and when you get to the viewing area directly overlooking two low-lying lagoon islands, a unique theatre of seabird life is revealed.

Tern populations have declined throughout their range in Britain and Ireland, and most colonies are on remote offshore islands, but at Cemlyn you can witness these ‘sea swallows’ close-up, as the parent terns come winging in over the shingle with dangling sandeels or sprats, calling to their hungry chicks.

Cemlyn has become a mecca for birdwatchers, photographers and film-makers, and in 2009 it played host to the BBC Springwatch team, who followed the progress of fledging chicks in detail.

Tern settling

Tern settling - Credit: Ben Stammers

Cemlyn is the only site where Sandwich terns breed in Wales and is home to the second-largest colony in Britain, holding around 20% of the UK population. Sandwich terns are large, powerfully-built terns, with shaggy black crests and yellow-tipped black bills.

Common and arctic terns also breed at Cemlyn in smaller numbers, and are similar to each other in appearance – black caps, red, pointed bills, long swallow-like wings and forked tails. All are migrants that winter on the coast of Africa, and all are elegant fliers and active fishers, plunge-diving for their prey.

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Historically, Cemlyn was also a breeding site for the endangered roseate tern. They are still recorded annually on passage, but since the 1990s, this enigmatic species has largely deserted Wales in favour of sites across the Irish Sea, where the overall population is now healthily increasing. Roseates, named after the pinkish blush on the breast which adults show in the spring, are particularly beautiful terns, with pointed black bills and very long tail streamers.

In partnership with other conservation bodies in Wales and the Republic of Ireland, North Wales Wildlife Trust is working on a new EU Life project to maintain and enhance Cemlyn as suitable roseate habitat, in readiness for their potential return. (

Birdwatching on the ridge

Birdwatching on the ridge - Credit: Ben Stammers

To help conserve the terns and other wildlife, the Wildlife Trust employs two seasonal wardens at Cemlyn. Based on site from late April to August, they protect the colony from disturbance and predation and monitor the breeding success of the different species.

Terns can nest very densely and the annual task of recording each and every clutch of eggs on the islands is not without its challenges – including aerial bombardment from protective tern parents. To give an idea of numbers, in 2014 there were 2,617 sandwich tern nests, 100 common tern, 39 arctic tern, 376 black-headed gull, and four Mediterranean gull.

Maintaining a constant presence at the viewing area on the ridge opposite the colony can be demanding and the wardens rely on back-up from dedicated volunteers who help out through the season. Not all are experienced ornithologists – the only requirements being a liking for the outdoors, an ability to observe, and a willingness to talk to visitors. The wardens welcome offers of help – even if only for an hour or two – for this important support role. If you’re interested in volunteering, contact the Wildlife Trust – and if that’s not for you, consider supporting their efforts to conserve terns for generations to come.

The summer wardens’ other priority is to engage with the many visitors to the reserve, offering up-to-date information, and close-up views of the action through a telescope. They may also point out one of the passing rarities that Cemlyn is famous for attracting.

The creature count at Cemlyn

The creature count at Cemlyn - Credit: Ben Stammers

Cemlyn is really an ideal site to inspire people about all kinds of wildlife. In addition to the terns, it is a great rockpooling location, and the unique coastal grassland hosts rare plants like yellow horned poppy and spring squill.

The Cemlyn Creature Count, which takes place this year on June 5, is an event designed for families and experts alike – a race to record as many species of birds, sea creatures, insects and plants as possible in two hours. w

North Wales Wildlife Trust operates 35 reserves across the region. For more information about becoming a member, their work and the events, or to volunteer, go online to

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