Police and wildlife experts have been trying to establish whether video footage shot at the proposed T in the Park site shows a protected osprey attempting to return to its old nest.
The clip was taken on Monday morning by members of a protest group battling to stop the music festival from being staged in the grounds of Strathallan Castle.
Wildlife charity RSPB Scotland called police to the estate on Monday afternoon after a copy of the video was passed to them by the Strathallan T Action Group.
T in the Park organisers DF Concerts have come under fire in recent weeks for using a large cherry picker, a saltire flag and a balloon to try to dissuade the osprey from returning to a nest on the 1,600-acre estate.
They want the birds to use a new nest built on a more secluded part of the estate.
If the bird settles, it may have serious implications for the future of the 21-year-old festival.
An RSPB Scotland spokesman said: “We were sent some video footage showing an osprey landing at the old nest at the Strathallan Castle estate.
“We have no means of authenticating it, but neither do we doubt that it is legitimate.
“If this is the case, the nest becomes active and the cherry picker must be removed as it is an offence to cause a disturbance at the nest under wildlife legislation as it is a protected species.”
He added: “As a result, we have contacted the police to have the cherry picker removed, so they are aware of it.
“As the nest is close to the planned site of the festival there are risks of it being disturbed.
“T in the Park will have to revise their plans because of this.”
A T in the Park spokeswoman said: “We’ve seen a copy of the video referred to by RSPB and it does not correspond with the ongoing monitoring from our ornithologist on-site.
“We are fully aware of and compliant with the legal protocol and, as such, we have asked the police and RSPB to seek further information so that the video’s authenticity can be fully examined.”
She added: “We have removed the cherry picker while we wait for this information.”
A resident who is against the festival plan said: “We are just waiting to hear what the police have to say.
“I have spoken to four people who have seen the video and they are convinced that it shows the osprey returning.”
A police spokesman confirmed that a video clip had been submitted to them by the Strathallan T Action Group.
“Inquiries are ongoing,” he said.
“We are getting assistance from RSPB Scotland and ornithologists.
“Police Scotland can confirm that reports have been received regarding concern about activity in the vicinity of an osprey nest in the Auchterarder area this afternoon.
“The matter is under inquiry.”
T in the Park had initially hoped to remove the osprey’s old nest from the estate but were refused permission by the landowner.
A planning application to relocate the festival to Strathallan, after organisers were forced to quit their old home at Balado, is expected to be decided next month.