Officers have received reports about the dead or injured creatures being found in the areas of Ravensdowne, Parade, Walkergate and Church Street – all in Berwick.
Inquiries are taking place following the spate of disturbing incidents, which have occurred over the last few months.
Berwick Neighbourhood PC Beth Spours said: “We are appealing for help from the community to identify those responsible for these incidents.
“We want to remind people that it is an offence to kill or injure seagulls. It is also very distressing for members of the community to find these dead and injured birds where they live. The people responsible may not only be committing offences by shooting gulls, but could endanger the public by using firearms in a public place.
Crossing closure will make railway line like the 'Berlin Wall' claims Blyth resident
Sea fret - a look at the foggy phenomenon which spoils sunny days in Northumberland
Missing man found
Six people and a dog rescued from stranded vehicles on Holy Island causeway
New addition to the Lowry Trail in Berwick
“We would also like to warn people that anyone found to be using an air weapon illegally may face arrest and possible prosecution.”
Police are appealing for witnesses who may have seen or heard anything suspicious to contact them.
Anyone with information should call police on 101, quoting reference number 258 29/06/16, or ring the independent charity Crimestoppers on 0800 555111.