at Northumberland Nature Reserve
A colony of one of the UK’s rarest breeding seabirds, devastated by Avian Influenza in 2022 and 2023 has produced more chicks than ever before. A record number of 191 Roseate Tern chicks hatched this year and 92% of those young birds went on to fledge (175 fledged out of 191 hatched).
The productivity of Roseate Terns (or average number of chicks fledged per nest) was 1.39 from 126 breeding pairs and this has only been beaten once before in the history of the colony when in 2017, 111 breeding pairs fledged 1.45 chicks (155 in total). This means the island also saw its second most successful breeding season yet for Roseate Terns, but RSPB experts say it is too early to say if this is a sign of recovery from Highly Pathogenic Avian Influenza.
For long lived species such as terns the recovery process could take many years and avian flu has not gone away - but the figures this year bring new hope for Coquet’s seabirds.
There was good news for Arctic Terns too, which fledged their highest number of chicks ever per pair at 1.49 and Common Terns fledged an above average number of chicks per breeding pair at 1.47 but the number of breeding pairs at 353 (compared with 1,875 Common Terns pre bird flu in early 2022) was the lowest ever recorded.
Just a mile off the Northumberland coast, Coquet Island is home to around 45,000 breeding seabirds and at present is the only Roseate Tern colony in the UK. Coquet also supports breeding Puffins, as well as Common, Arctic and Sandwich Terns, Eiders, Razorbills, Fulmars, Kittiwakes, and Herring, Lesser Black-backed and Black-headed Gulls, and is protected under international and UK law.
Conservationists say that 276 adult Roseate Terns seen on Coquet Island this year hatched during or before 2022, when the disease first took hold on the island. This also brings hope that some of these birds survived the virus, but it’s also possible some of these birds did not catch it. This data is collected by dedicated staff and volunteers who spend many hours using a telescope to read leg rings which are marked with a unique code to identify each bird individually.
Roseate Terns are a threatened Red Listed species in the UK, meaning they are at the highest-level of conservation concern. Expert conservationists and volunteers at the RSPB work year-round to provide the right conditions for these birds to thrive, protecting them from disturbance, as well as monitoring them through ringing to enable tracking of their movements and calculation of survival rates. Roseate Terns like to nest in boxes on open terraces and this autumn the team of staff and volunteers has been busy clearing all the vegetation off the terraces and repairing them.
Stephen Westerberg, RSPB Northumberland Coast Site Manager, said:
“Here in Northumberland, we have the only colony of this elegant seabird in the UK. Knowing that the Roseate Terns have had such a successful breeding season after two years of bird flu gives us great hope for the future.
“There are still a lot of unknowns though, and we could see outbreaks of Avian Influenza in subsequent breeding seasons on Coquet. We hope though that next year will bring another successful breeding season for our Roseates but surveillance and preparedness for outbreaks is key”.
Despite the good news, the numbers of Roseate Terns returning to nest on the island this year were lower than in recent years and the hope now is that these numbers will increase next Spring. In 2022, thanks to many years of targeted conservation work, their numbers had grown to 154 pairs before then being hit by bird flu.
It is not known exactly how many Roseate Terns died from Avian Influenza and some may have died away from the colony, but 2023 RSPB seabird surveys revealed a 21% decline in the Coquet breeding population since before the bird flu outbreak. This year drones have been used for the first time to count the nesting birds, using trained and licenced drone pilots and in addition over 3,000 bird rings have been read by staff and volunteers to find out where Coquet’s seabirds are coming from and how long they live for.
Avian Influenza remains a threat to seabirds and between September and October this year, 20 Great Black-backed Gulls were found dead on Coquet Island, with samples testing positive for a different sub-type of bird flu to that seen in 2022 and 2023.
All the seabirds apart from the larger gulls have now left the island, and for the terns, that means migrating down to West Africa and beyond, where they will spend the winter, before returning to Northumberland in the Spring, when conservationists will wait to see if they return in larger numbers. If enough of our vulnerable seabirds already exposed to Avian Influenza have developed immunity, flock immunity might protect against large-scale outbreaks. Immunity though, wanes over time and the virus can change.
Stephen added: “We urgently need action from the UK governments to tackle the many threats our seabirds face so they can recover in numbers and reach healthy population sizes better able to withstand threats such as disease.”
In total 28 species of birds nested on the island in 2024, including seven species of duck. The oldest Roseate Tern, aged 13, returning to Coquet this year will have travelled at least 84,000 miles on its migration, the equivalent of traveling three times around the world.