Feeding frenzies and resurgent glowworms among UK wildlife highlights in 2023 | Wildlife

Spectacular feeding frenzies of Atlantic bluefin tuna, surging numbers of glowworms, and a record-breaking breeding season for pied flycatchers are among the British wildlife highlights of 2023.

But conservationists warned that overall wildlife continued to decline, with one in six species at risk of extinction – and that wildlife was being challenged in new ways by global heating, disease and other destructive human activities.

There were multiple reports of “bait ball” feeding frenzies from Scotland to the Isles of Scilly involving whales and dolphins as well as bluefin tuna. These spectacles occur when predators force fish such as mackerel to cluster together in a dense ball before cetaceans and tuna as well as opportunistic seabirds plunge in to feed on the prey.

The rise in sightings of bluefin tuna, once common in British waters, is linked to restrictions on fishing over the past 15 years, as well as warming seas. Bluefin tuna has now been removed from the International Union for Conservation of Nature (IUCN) red list of endangered species and limited fishing in UK waters has resumed.

Dr Lissa Batey, head of marine conservation at the Wildlife Trusts, said: “This fantastic fish has returned from the brink of extinction and the risk of decimating the population for a second time remains high – so it is vital that commercial fishing quotas are set realistically and rigorously enforced. When we give nature space, wildlife can recover – it’s as simple as that. We must act faster to protect the UK target of 30% of seas by 2030.”

On land, success stories included the highest number of glowworms – 303 glowing females – at Whitecross Green Wood nature reserve in Oxfordshire since recording began there in 1999, and record numbers of natterjack toadlets in Cheshire. In both cases the rare and declining species were boosted by targeted conservation management.

In 1975 not a single military orchid was counted at Homefield Wood reserve near Marlow, which is managed by Berkshire, Buckinghamshire & Oxfordshire Wildlife Trust (BBOWT). This year a record 1,111 were counted and were assisted by volunteers painstakingly fitting protective shields around each plant to stop deer and rabbits devouring the rare flowers.

In another sign of the changing climate, a southern migrant hawker dragonfly was recorded breeding in Oxfordshire for the first time – with many species of dragonfly expanding their range in Britain because of global heating.

Colin Williams, senior ecology officer at BBOWT, said: “Getting record numbers of glowworms or seeing new dragonflies is great – but this is almost entirely down to decades of incredible work by our staff and thousands of tireless unpaid volunteers creating robust and diverse habitats.

“The wider picture for wildlife in our three counties is incredibly distressing, and nature is in crisis across our region. We’re doing our best to hold on to things we still have until we can reverse those trends.”

While winter birdwatchers were cheered by watching large numbers of migratory waxwings, in summer record numbers of migratory pied flycatchers were recorded nesting in some RSPB woodlands.

Volunteers installing specially designed nest boxes and clearing the dense holly understorey has helped the flycatcher, with woodland management enabling flowers such as wood anemone and wood sorrel to flourish, attracting more insects on which the acrobatic flycatchers feed.

At RSPB Haweswater in the Lake District, 29 singing males of the amber-listed species were counted, suggesting a total population of 50 to 60 pairs across the reserve, the highest number for a decade. A record 66 birds were recorded in RSPB Coombes Valley and Consall Woods in Staffordshire.

Spike Webb, RSPB warden at Haweswater, said: “This summer we had the best number in 10 years. Given that these birds come all the way from west Africa in spring to breed here in the Lake District, it’s always a joy to see them back in the forests of Haweswater and especially when their numbers are so good.”

But many British seabirds are continuing to decline. A survey of the Isles of Scilly by the RSPB and the Isles of Scilly Wildlife Trust found a 20% decline in seabirds since 2015 in what is one of England’s most important colonies. Common terns vanished as an annual breeder, with kittiwakes set to follow and big declines for lesser black-backed gulls (58%) and the red-listed herring gull (40%).

Although there were signs of some birds showing immunity to avian flu – with gannets on Bass Rock, Scotland, which have black instead of pale blue irises, more likely to have survived the virus – large numbers of seabirds continued to die from the disease.

The tern colony at Cemlyn Nature Reserve in north Wales has halved in size since 2022 because of avian flu, with 1,200 dead terns collected there in 2023. Dorset Wildlife Trust recorded 600 dead birds on Brownsea Island during the breeding season, mainly sandwich and common terns, and black-headed gulls.

Exciting marine sightings included 156 sightings of Risso’s dolphins in Cornwall, compared with 45 last year, and more than 20 fin whales off Cornwall alone, compared with fewer than five sightings in 2022. A male orca was also spotted three miles offshore from Bempton Cliffs, the first sighting off Yorkshire’s coast since 2007.

Most of Britain’s existing marine conservation zones are dismissed as “paper parks” by conservationists because they do not prevent highly destructive fishing such as trawling in the areas.

But the government this year created a scaled-back list of the first ever highly protected marine areas (HPMAs) in English waters, with protected zones at Allonby Bay, in Cumbria; Dolphin Head, in Sussex and north-east of Farnes Deep in the North Sea.

Battey said: “This new gold-standard of protection will stop all damaging activities such as trawling and enables marine wildlife to recover, benefiting fishers and carbon-storing habitats. These special places cover less than half a percent of English seas – so it’s a tiny first step towards more designations.”