Road deaths are having a massive impact on barn owls in the South West, according to a major study.
Barn owls are being killed in huge numbers on the roads
The number of barn owls nationally has gone down by almost 70% since the 1930s, mainly because of intensive farming and developments on green field sites.
But half of all recorded deaths of barn owls are road casualties.
The study was carried out by the Devon-based Barn Owl Trust over a 15-year period and shows that, unless action is taken soon, the UK barn owl population is unlikely to recover.
The trust is now using the results to put pressure on farming and highways authorities.
There are now only 4,000 pairs of barn owls left in the wild.
Each year, they will produce 10,000 young owls, but about 3,000 of those birds are being killed in road accidents.
The research showed that in the nesting season, from March to August, all adult barn owls whose nest site is within half a kilometre (0.3 miles) of a major road are almost certain to be killed.
Road deaths also have more impact on barn owls than any other creature.
The trust, based in Ashburton, is now calling for a complete end to new major roads being built in rural areas where barn owls are present within a 25 kilometre (15.5 mile) radius.
The trust wants to see more barn owl-friendly habitats on farms
This includes motorways, dual carriageways and local bypasses.
Continuous three-metre (10 feet) high screens of trees and hedges should also be provided alongside existing main roads, so barn owls can fly over the traffic.
The charity also wants to see more barn owl-friendly habitats created on farms, but well away from main roads.
Trust spokesman David Ramsden said: "We've known for many years that barn owls are being killed on roads because we've been picking up the casualties.
"One of the really important findings is that the animals being killed in road accidents are those which would have lived.
"Road accidents are killing those which have survived through their early life."