An investigation has started after two seagulls were found with crossbow bolts through their heads in Scarborough.
Last month a gull was found with a silver bolt pierced through its head and now a second bird has been spotted with a black bolt lodged in its head.
RSPCA staff are trying to find the birds, who are believed to still be alive, so they can treat them.
The animal welfare organisation's Inspector Geoff Edmond described the incidents as "appalling".
He said: "It is absolutely appalling and completely illegal to be shooting birds in this manner.
"This is a concern as it looks like there are two seagulls flying around injured, and a concern that somebody has been shooting at them."
The Royal Society for the Protection of Birds (RSPB) also condemned the attacks.
Investigations officer James Leonard said: "These attacks are shocking, barbaric and illegal under the Wildlife and Countryside Act."
Graham Rhodes, who runs the town's Aakschipper Gallery, spotted one of the injured birds and took a photograph. He said the bird appeared to be unharmed by the bolt.
"I walk my dog in the area twice a day and I see the seagull every time," he said.
"It appears to be carrying on as normal despite having a bolt through its head."