The RSPCA is investigating after two swans were found dead at Lake Grounds in Portishead.
The birds were found by a resident, who said one of the birds appeared to have been beheaded.
There has since been speculation and anger on social media as to the possible causes of death - but the RSPCA told ITV News the birds could have been attacked after death by other wild animals.
And North Somerset Council has told the police neighbourhood team they have no concerns about any human involvement in the deaths.
A spokesperson for the RSPCA said: “This must have been a saddening and shocking discovery for the person who found the swans and contacted our rescue team.
“The bodies of the swans have been examined by a vet who has been unable to establish an exact cause of death.
“We would urge anyone who has any evidence of deliberate animal cruelty to contact the RSPCA’s cruelty line on 0300 1234 999.
“All wild birds, including swans, are protected under the Wildlife and Countryside Act 1981 and it is an offence to kill, injure or take them without a licence.
"The maximum penalty, if found guilty, is six months in prison and/or an unlimited fine.”