Wild deer should be hunted for venison to reduce populations and help woodland birds, experts have said, as the the nightingale was added to the list of threatened species for the first time.
The British deer population now stands at around 1.5 million, the highest level it has been for 1,000 years, with numbers doubling since 1999.
But while deer are thriving, woodland songbirds are in serious decline with species such as the turtle dove dropping 77 per cent in the last decade. The RSPB’s latest State of the UK Bird report added nightingales and pied flycatchers to its red list of the most threatened.
Dr Markus Eichhorn at Nottingham University’s School of Life Sciences, found that when dense deer populations are present in woodland there is 68 per cent less foliage below two metres, which ground-nesting birds like nightingales rely on for breeding.
He suggests the problem could be solved by hunting deer and re-establishing venison as a British dietary staple.
"It is clear from our research that if we want to encourage more woodland birds then we need to take action to restore the woodland structures they require but in many areas it will need a drastic reduction in deer to have any real impact,” said Dr Eichhorn, who published his findings in the Journal of Applied Ecology.
"We should not think of it in terms of a cull. We already eat venison in Britain but a large proportion of that is farmed meat. If wild-caught deer appeared on our menus or in the local butchers it would encourage people to eat venison as readily as beef or lamb and would help conservation in our woodland areas."
Deer populations have been steadily increasing since the 1963 Deer Act stopped the animals from being treated as vermin, and now hunters require a licence. They also have no natural predators, such as lynx or wolves and each year are responsible for around 50,000 traffic accidents and the death of around 20 people.
Working with the British Trust for Ornithology (BTO), Dr Eichhorn set out to establish the implications for our woodlands of the large the deer population, which includes both the indigenous species of Roe and Red deer, as well as later invasive species such as the Fallow deer which was introduced by the Normans and Reeves' muntjac, Chinese water deer and sika deer which arrived on our shores in the late 19th and early 20th centuries.
The study produced 3D images of of 40 woodland areas in England allowing a detailed analysis of whole forest structures from the ground to the treetops and quantified for the first time the series impact that populations were having on songbird habitats.
The RSPB report also found that more than one quarter of British birds are in urgent need of conservation with the puffin, curlew, dotterel, whinchat, grey wagtail and merlin also joining the growing list of threatened species.
The curlew is also now considered ‘near threatened’ globally and with urgent action required to halt their decline, an International Single Species Action Plan has been created. The RSPB said that
Dr Daniel Hayhow, RSPB Conservation Scientist, said: “Wild deer are an important part of our woodlands. However, without natural predators there is a risk that deer populations left unchecked could be damaging to habitats and wildlife.
"Greater demand for wild venison, and better management of our wild deer herds could be beneficial to our woodlands, giving vegetation more chance to regrow and providing conditions that would encourage more species to share our woodland.
"However, any hunting must be sustainable and help to maintain a natural balance rather than motivated solely by the demand for meat.”
The RSPB report contained good news for some species. Golden eagle numbers have increased by 15 per cent since the previous survey in 2003. There is good news for cirl buntings too, which are now estimated to have over 1,000 breeding pairs. The winter thrushes survey shows how important the UK is for continental migrating birds.
Two species, the bittern and nightjar, have moved from red to amber thanks to conservation management while 22 species, including the red kite, have moved from the amber to the green list meaning they are now of the lowest conservation concern.