The willow tit has become Britain’s fastest declining resident bird, and one of half a dozen imperilled woodland species, according to the definitive survey of the country’s birds.
Numbers of the diminutive tit, a subspecies unique to the UK, have plummeted by 94% since 1970, and by a third since 2008.
The willow tit, which lives in dense birch thickets close to wetlands or water, has almost entirely vanished from south-east England and now survives mainly in post-industrial sites such as former coalmines, north-east of Derbyshire.
Woodland birds have slumped by 27% since the 1970s and are continuing to dramatically decline, falling by 7% over the past five years, according to the new report. The breeding populations of five rare forest-dwelling species – lesser spotted woodpecker, lesser redpoll, spotted flycatcher, capercaillie and marsh tit – are now less than a quarter of what they were 50 years ago.
Fiona Burns, lead author of the report produced by the RSPB, the British Trust for Ornithology (BTO) and the Wildfowl & Wetlands Trust (WWT) together with the government’s nature conservation bodies, said: “The UK’s birds are telling us that nature is in retreat. The continuing losses seen across many species are not sustainable and more needs to be done to stop the declines and help populations revive and recover.”
According to Mark Eaton, principal conservation scientist at the RSPB, the willow tit’s decline is caused by a burgeoning wild deer population eating out dense thickets and the scrubby under-storey of many woodlands, the drying out of soils caused by the climate crisis, and the fragmentation of woods because of developments such as housing, new roads, and new railways. All three trends are particularly pronounced in the south-east.
While a few woodland species such as goldcrest can survive in non-native conifer plantations, such new forests – being planted in part to offset carbon emissions – will not help the declining birds.
“The easiest solution to our lack of trees is a very poor solution for these struggling birds,” said Eaton.
The Breeding Bird Survey also shows a continuing decline for “farmland” birds, including Britain’s fastest declining bird, the migratory turtle dove. Farmland birds have continued to decline by 5% between 2013 and 2018 with an overall decline of 45% on 1970 populations.
But Eaton said the prognosis for farmland birds was more hopeful, with conservation science better understanding the reasons for their declines, and agri-environment schemes – where farmers are paid for nature-friendly practices – being scientifically proven to boost bird numbers.
With the government promising that its new post-Brexit farm support, the Environmental Land Management Scheme (Elms), will provide money for farming that produces “public goods” such as healthy soils and wildlife-rich countryside, Eaton said there were “reasons to be cautiously optimistic”.
“We know agri-environment schemes work,” he said. “It’s having them at sufficient scale across enough farms to really turn things around at a population level. Certainly in England there’s the potential for that scale to be achieved [with Elms].”
One thriving farmland bird is the wood pigeon, which is singlehandedly responsible for the biomass of native British birds actually rising since the late 1960s, despite the loss of 19 million pairs of native birds, to leave a population of 83 million native pairs.
Smaller birds have declined in number – 10.7 million pairs of house sparrows have vanished – but the wood pigeon has added 3,300 tonnes of biomass to the UK total of 20,000 tonnes. The wood pigeon has prospered with the intensification of arable farming, fattening up on winter-sown crops and oilseed rape.
According to Eaton, Britain’s bird populations show signs of “biotic homogenisation”, which means there are fewer species thriving but some adaptable “generalist” species such as wood pigeons are thriving, while species with very particular needs, such as willow tits, are disappearing.
Britain’s 83 million pairs of native birds are joined each summer by 57 million non-native pheasants and partridges, which are released to be shot.
While fieldfares and golden orioles are close to becoming extinct as breeding birds in Britain – not helped by global heating pushing their natural ranges northwards – there is some good news.
Climate warming has helped large waterbirds colonise Britain, with cattle egrets now following little egrets, little bitterns and spoonbills to breed successfully, helped by improved legal protections for the birds and their wetland habitats.
Populations of some of Britain’s rarer breeding birds have also increased, with cirl buntings, stone-curlews and corncrakes responding to targeted conservation action.