Motorists travelling to work along a scenic country road were forced to swerve around the carcasses of up to 100 pigeons.
The bodies of the dead birds were strewn along the road between Telscombe village and Rodmell on Friday morning.
The corpses were lying at the sides of the road and at one point right up the centre of the road. Many of them had been squashed under the wheels of vehicles.
Motorist Alan Hetherington, from Peacehaven, was taking his partner to work in Burgess Hill.
He said: "It was like a butcher's shop. It was a massacre. There were about 70 pigeons on the road in a 100m stretch."
Several of the dead birds were found in plastic bags.
Mr Hetherington thinks they could have been killed during a shoot. He believes someone collected the dead birds up in plastic bags and loaded them on to the back of a truck, not realising they were falling off the back when they drove off.
He picked up two of the birds and placed them in the boot of his car to take to a veterinary clinic in Peacehaven for an examination.
He added: "They've definitely been shot. I counted at least 72 of them."
Trevor Weeks, rescue co-ordinator for the East Sussex Wildlife Rescue and Ambulance Service (WRAS), said: "The two birds will be examined.
"At this point I wouldn't like to say how they have died. If they have been shot and killed it's not illegal."
Mr Weeks said the dumping of animals in this way would be a breach of the 1990 Environmental Protection Act.
Those found guilty faced fines of up to £5,000.
He plans to report the incident to police and Lewes District Council.
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