Two nests of herring gull chicks have been orphaned after the death of three adult birds who were illegally shot.
The RSPCA said the birds are believed to have been attacked with an airgun in the Cornish holiday resort of Newquay over the weekend of 21 and 22 June.
Two gulls were shot dead and the third was seriously injured and had to be put to sleep by a vet.
The chicks were rescued by the fire brigade and are being cared for at the RSPCA's wildlife centre in Somerset.
Animal collection officer Felicity Cross said more birds could have been shot and not yet discovered.
"It seems that someone is taking pot-shots at these birds because they are relatively easy targets," she said.
"Possibly they realise that without a parent the chicks will starve to death, which is a very cruel and callous approach to take."
Herring gulls are considered pests by some people, but under the Wildlife and Countryside Act 1981, it is illegal to kill them without a licence.
The RSPCA has appealed for anyone with information about the attacks to contact them.
"Not only is this behaviour cruel and anti-social, it is illegal," Ms Cross said.
"People may think they can shoot gulls as they please, but they are protected."
On Monday a 21-year-old man was arrested in Exeter after reports of seagulls being shot at with a BB gun.