A gang of poachers described as being of Arabic or Mediterranean appearance were spotted dragging a young swan from the river Trent in the village of East Stoke, near Newark, police said last Friday.
The gang dragged the young bird up the bank by the neck and it is thought the motive was to eat the bird as a delicacy.
The incident was witnessed by an angler fishing the river at the time and follows hot on the heels of claims that asylum-seekers are hunting and trapping waterfowl for food.
Police were told that he saw the man dragging the bird by the neck, apparently unconscious, out on the opposite bank to the one he was fishing with his father.
The angler shouted across at the man and as he did so, three or four other men appeared from the undergrowth, grabbed the bird and ran off, a police spokesman said.
Wildlife officer PC Doug Kent said: “I don’t know what else they would do with a swan but eat it.
“I would guess it was going to be eaten. It seems like there has been a similar problem in the Metropolitan Police area but at the moment this is the only one in Nottinghamshire that I have heard of.
“Unfortunately it could be part of a bigger problem.”
A spokesman for the RSPB said: “We were made aware this morning that there was a crime that had been committed involving a swan.
“We have received reports of people taking the birds and eating them.”
“Anyone spotted harming a swan could face a fine of up to £ 5,000 or six months imprisonment,” he added.
