A bird snatcher has been caught red-handed trying to swipe rare eggs from a nest monitored by the RSPB.
Pictures of a hand taking a stone-curlew egg were discovered when workers from the RSPB viewed the images from a camera set to monitor a nest on Salisbury Plain, Wiltshire.
The same hand was then snapped moments later replacing the egg before someone returns about 12 hours later and moves the camera to point away from the nest.
The camera was turned off altogether four days later.
It is thought the eggs were taken as there was no evidence in the nest of them hatching.
The images were taken sometime in the middle of July and a £1,000 reward has now been offered for information leading to the conviction of those involved.
Andrew Taylor, one of the RSPB's field workers, said: "We went to retrieve the camera and images once we thought the young birds had hatched and left the nest.
"But when we loaded them on to our computers we could not believe what we were seeing - a human hand lifting the eggs.
"Fearing the worst, we went back to the site to investigate further.
"The nest, just a shallow depression in the ground, had no sign of any eggshell remnants, a sad indication that the eggs might have been taken rather than hatched.
"While viewing one of the adults later, we saw the bird scraping the ground to create another nest, again, a reliable indication of nest failure.
"Although we cannot be absolutely sure, this all points almost undoubtedly towards the eggs being stolen."
Stone-curlew are a nationally rare species and the RSPB with support from Natural England has spent more than 20 years working with farmers and land owners, including the Ministry of Defence, to reverse the historical decline of the bird of the Wessex chalk downland.
Ian West, head of investigations for RSPB, said: "Egg collectors still pose a threat to our scarcest species.
"In this case, all the evidence points towards the eggs being taken which, if so, is a tragedy for the birds and for this wonderful species.
"It continues to sadden me that despite egg collecting being a crime, and despite increased fines and the threat of custodial sentences, there is still a sad minority of individuals out there intent on pursuing this cruel obsession with the eggs of our wild birds."
Anyone with information about the theft can call the RSPB's investigations team in confidence on 01767 68055