Seagulls have been beheaded and laid out on a beach in what may have been a gruesome ritual.
Mutilated gulls were found at Saltdean beach this week.
Residents have reported birds being stoned to death and shot and wildlife charities said they have seen an unprecedented number of seagull killings in Sussex this year.
Saltdean residents said they knew of at least 15 cases of birds killed in the last fortnight and suspect the number may be higher with dead seagulls seen floating out to sea.
Christine Carruthers, of Westfield Avenue South, Saltdean said: “There are at least three that have had their heads cut off and had been laid out like a ritual.
“It’s absolutely appalling.
“There are now a lot of young ones on their own that cannot fly because their parents have been killed.
“At first we thought it was just a one-off but it’s obviously not.
“We think whoever is doing it must be going out late at night or very early in the morning.”
Another Saltdean resident who did not wish to be named said: “One of the birds died outside my door and her two babies are down on the beach.
“People don’t realise they have been shot until you ruffle their feathers and find a bullet wound.
“I’ve never heard of anything like this before.”
Alex Szabo, founder of the South Coast Animal Ambulance said that they had dealt with 30 bird attacks in the last fortnight - the most they had ever seen.
He said that gulls had been shot by BB guns and been cut with knives in various incidents between Saltdean and Brighton Marina.
He added: “We are taking this very seriously and we want to warn people that this behaviour is not acceptable.”
Roger Musselle from Roger’s Wildlife Rescue said he had been called about more dead gulls so far this year than any other year.
He added: “The beheading might be due to a fox, they do like heads but are not that partial to gulls.
“It’s a pity that somebody hasn’t been prosecuted already but we haven’t been able to catch anybody in the act or witnesses don’t want to go through reporting them.
“Even though they are on the red list of endangered species worldwide, most residents seem to think they are vermin but I consider people who treat wildlife like that as vermin.”
A Brighton and Hove City Council spokesman said: “We’re aware of reports of dead gulls being found on the beach in Saltdean and our beach cleaner has found several.
“However we cannot confirm how these birds have died - whether it’s due to human activity or in the case of younger birds, predation.”
l IT is a criminal offence to kill or deliberately injure a seagull. Anyone caught killing a gull could be fined up to £20,000 or sentenced to six months in prison.
All 11 species of seagull found in Britain, including the most commonly seen herring gulls, are protected species under the Wildlife and Countryside Act 1981.