Protective netting installed on a 17th century thatched barn in Avebury is to be partly removed following concerns it is helping birds to rip the straw out.
It is thought jackdaws use the netting to get a grip on the steep roof of the Grade I-listed barn in Wiltshire.
It was installed by the National Trust in 2016 after birds attacked the barn following a £100,000 re-thatch.
The trust said the "intelligent birds" had "learned to work together to pull down the netting to get to the thatch".
The trust has tried "umpteen solutions" including dummy birds of prey to try and stop jackdaws picking the thatch to pieces, without success.
Now it plans to remove the netting on an area of the historic building.
"It is believed this will make it more difficult for jackdaws to gain a purchase on the surface of the thatch," the trust said in a statement.
"Due to the steep angle of the roof, it may reduce their ability to pull the individual straws out."
Jackdaws admiring their destruction of the tithe barn thatched roof at Avebury, Wilts. The Grade 1 listed building was rethatched with straw in 2013, but the 'daws wanted it thatched with Norfolk reed and have pulled the straw out ever since, despite netting. pic.twitter.com/UCp7bR6END— Matthew Oates (@MatthewOates76) February 14, 2020
The trust said it was "learning as it goes" and only "time will tell if this new method works".
"The risk is that [removing netting] may increase damage caused by other vermin, so there will always be a trade-off," it said.
The former threshing barn is now used as a museum and visitor's centre for the nearby Neolithic stone circle.
All wild birds in the UK are protected under the Wildlife and Countryside Act 1981.