Wild deer should be hunted for meat to increase the UK's woodland bird population, an ecology expert suggests.
Markus Eichhorn, from the University of Nottingham, said Britain's large deer population was damaging natural habitats and hurting bird numbers.
He argued hunting deer for venison would help to reverse a decline in the number of ground-nesting birds including the nightingale.
Animal rights group, Animal Aid, said the move would be "highly unethical".
Dr Eichorn led a team of academics commissioned by the government to study the causes behind the decline of woodland birds such as the nightingale, marsh tit, willow tit and lesser-spotted woodpecker.
All four birds are on the RSPB's red list and have suffered a "severe" decline in their breeding populations in the past 25 years.
In that time it is believed the population of the UK's deer has risen from about one million to about two million.
Comparing 40 woodland areas in England, the team found in areas of dense deer populations there was 68% less foliage near the ground compared with areas with fewer deer.
Dr Eichhorn said deer populations were at "extraordinarily high levels" due to the absence of large predators, among other reasons.
"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.
"We [should] start eating wild-caught, free range British venison given that it's abundant and wildly available."
A spokeswoman for Animal Aid, an animal rights groups, said deer should be treated with respect.
She said: "It is humans that have caused deer populations to increase and these majestic animals should not be forced to pay for our mistakes with their lives."
Animals rights group PETA said: "Ecological harmony will never be achieved through the barrel of a gun."
Deer in the UK
- There are about two million red, roe, fallow, sika, muntjac and Chinese water deer in the UK
- The 1963 Deer Act gave the animals protection and controlled who could shoot them and how
- Deer do play a part in the health of woodland ecosystems but "over-browsing" can also have a negative effect
- Historically the animals would have been preyed on by bears, lynxes and wolves
- It is believed numbers may have doubled since 1999, coinciding with the decline of some woodland ground nesting birds
- The Deer Initiative has been exploring what can be done to control numbers in England since 1995