One theory is that the seagulls have been consuming booze left behind on beaches by boozed up revellers, another that they've been swooping in on grain by-products from a local brewery.
Other sources report that the seagulls' freakish behaviour could be nothing to do with alcohol, but instead the consumption of flying ants which produce formic acid, a substance that "stupefies" the birds. According to the charity, the birds are reacting in pretty much the same way as humans do when they drink too much.
Some of the birds were found unconscious, and from them smelled of alcohol.
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The charity is urging local breweries, distilleries and alcohol producers to check that their waste is secure and can not be accessed by wildlife or birds.
"This year there has been a spate of cases with birds from east Devon, Dorset and Somerset".
"Drunk" gulls who appear disoriented, confused and struggle to stand have been picked up along the south coast.
A veterinarian with the animal welfare charity told Sky News a few of the seagulls have died after showing symptoms of intoxication, but many are recovering.
Anyone who has any concerns for the welfare of a bird or any animal can contact the RSPCA's 24-hour helpline on 0300 1234 999.