Three dead birds were discovered floating in the backwaters of Walton-on-the Naze with multiple shot wounds in what has been described as a 'sinister incident'.
The bodies of a pair of mute swans and a black-headed gull were all found floating by the side of the river by a passing boatsman.
They were all covered in what appeared to be multiple shot wounds and had become caught in the bushes, according to the RSPCA.
RSPCA inspector Sarah Elmy said: "This feels like quite a sinister incident.
"The reports are that there were shot wounds all over the birds' bodies - including the head. They were found drifting to the side of the water all together.
"It seems that someone must have gone out here to shoot birds with intent.
"The three dead birds were found too close to each other for this to be an accident, and these backwaters are not areas where people are likely to be just passing with a weapon.
Anyone with any information should contact the RSPCA in confidence on 0300 123 8018.
