‘Tern’ in fortunes for graceful seabirds on UK coast

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Rangers hopeful of about ‘tern’ in fortunes for graceful seabirds at Long Nanny after colony devastated by bird flu last year.

National Trust Rangers who keep close watch over Britain’s largest mainland colony of Arctic Terns at Long Nanny on the coast of Northumberland are holding their breath at a critical time in the breeding season to see whether the colony has managed to escape avian influenza, bird flu, this year.

Arctic Terns migrate from their northern hemisphere breeding grounds to Antarctica and back – a journey of up to 50,000 miles each year.

The coastal site is typically a safe breeding ground for both the Arctic and Little Tern, the latter being the second rarest breeding seabird in the UK, which has a much shorter migration to and from the west coast of Africa, each year. 

Arctic tern fledglings on the Northumberland coast at Long Nanny | © National Trust Images/Mandy Fall

Last summer over 1,000 Arctic Tern chicks and several Little Tern chicks perished due to bird flu – threatening to undo some of the gains made to the population in recent seasons, 

This year the number of adult breeding birds are lower, but not as much as the six rangers who guard the colony during the breeding season feared, with the number of nests with eggs this season down by 20 per cent: 1,040, compared to 1,300 in 2023. 

James Porteus, Area Ranger at Long Nanny says:

“By this time last year, we had the first few cases of bird flu confirmed and sadly 1,329 Arctic Terns died from the disease (1,066 chicks and 263 adults). 

“The good news is that the number of returning adults is higher than we hoped, with well over 2,000 breeding adults recorded. Most birds have successfully laid eggs which have now hatched. We are now on tenterhooks to see how the chicks fare – and are hoping that they make it through these critical first few weeks and are able to survive the annual pressures of predation and extreme weather due to climate change. 

“Our monitoring data contributes towards the national seabird monitoring scheme and we will need to understand how populations are faring across UK sites (& Europe) before we can make a full assessment of the impacts of bird flu on our internationally important seabirds.”

The Little Tern colony which returns each year to breed is far smaller and the number of returning pairs are down by a third with a minimum of 24 pairs this year, compared to 37 pairs in 2023. 

James continued:

“Any drop in Little Tern numbers is very worrying. The number of breeding pairs has been gradually declining over recent decades, from approximately 2,000 breeding pairs in England in the 1980’s to roughly 1,400 pairs today. Habitat loss and recreational disturbance along our coast is impacting our Little Tern population and reserves such as the Long Nanny are so important to the future of this species in the UK.” 

Initially helping compensate a little for the heartbreak of the last year’s bird flu outbreak, the team have also confirmed the first known breeding attempt between an American Black Tern and Arctic Tern. However, although three eggs were successfully laid, it now seems that they are unlikely to hatch given the period of time which has now passed.

Closely monitored by the ranger team and Professor Chris Redfern from Newcastle University, he says:

“Black Terns from Europe visit the Northumberland coast occasionally each year, but to get one of the American subspecies is very rare indeed. It is even more unusual for such a bird to pair up with a very different species of tern. 

“Black Terns lay smaller eggs than Arctic Terns, and we now know that the Long Nanny American Black Tern is female. Although the eggs appear to have been fertile, hatching is well overdue and we suspect that the species difference between Arctic and Black Terns is too wide to allow healthy, living chicks to develop.

“Terns are loyal to their partners, so despite it now looking very unlikely that these eggs will hatch, it will be interesting to see if they try again next year.”

Visitors to the area are requested to avoid disturbing any of the birds at Long Nanny by keeping a safe distance from the colony and keeping dogs on a short lead at all times during the next few critical weeks.

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