A charity dedicated to the conservation of barn owls is carrying out a major survey of their numbers in Devon, the first for a decade.
There are between 250 and 350 pairs in Devon
Barn owls were once a common sight across Devon, but intensive farming has led to a serious decline in their numbers.
Now the Ashburton-based Barn Owl Trust is holding a census between April and September 2003, the first since 1993.
The Devon Birdwatching and Preservation Society will also assist with the survey.
The creatures used to thrive in Devon, but the switch to intensive farming since World War II has meant much of their natural habitat has disappeared.
We are asking farmers to leave a small corner for barn owls
Sue Searle, Barn Owl Trust
"Barn owls need rough grass where there are small mammals," said Sue Searle, assistant conservation officer at the Barn Owl Trust.
"These areas have largely gone because of intensive farming, and we are asking farmers to leave a small corner for barn owls.
"Hedgerows also help, but these are often cut back."
Since the 1930s, the number of barn owls in the UK has fallen by 70%.
Nationally, there are now around 4,400 pairs, and in Devon, there are between 250 and 350 pairs.
Hotspots include parts of north Devon, and the area between Torbay and Totnes in south Devon.
Barn owl staff and volunteers will be visiting over 1,000 possible barn owl sites in Devon during nesting time to get an idea of their numbers.
"Hopefully, we should have an idea how many pairs there are by the autumn, and our census report should be complete by the end of the year," said Ms Searle.