Staggering around, unconscious, and “reeking of beer,” British seagulls are doing a fine impersonation of thirsty holidaymakers on England’s Southwest coast. Yet, the case of these drunken seagulls has left animal rescue workers mystified.

As reported by Devon Live, during the past fortnight, over two dozen ‘drunk’ birds have been taken into RSPCA animal rescue centers, with birds said to be “in such a state that they are almost unconscious.”

Local news sources suggest the gulls are becoming intoxicated on half-finished cups of beer, but the RSPCA, Britain’s largest animal welfare charity, remains unconvinced.

Speaking to Devon Live, a spokesperson for RSPCA West Hatch said, “I’m almost positive it is not that they are drinking beer left on beaches as they have all eaten a substance that they have brought back up.”

They added, “Our suspicion is that it is a by-product of the brewing process, as they all seem to have eaten the same thing.”

The RSPCA has urged local breweries and distilleries to ensure that wildlife cannot get to their waste. But, this theory, too, is problematic, given that spent grains from the brewing process typically contain little, if any, alcohol.

Speaking to the BBC, RSPCA officer Jo Daniel said, “… the birds absolutely stink of alcohol when we collect them so now our vans smell like pubs.”

Meanwhile, another possible suggestion is that symptoms are actually unrelated to alcohol consumption. In previous years, gulls have reportedly exhibited drunken behavior after eating scores of flying ants, yet this theory fails to explain why intoxicated birds are left smelling like alcohol.

One thing’s for sure: Just like humans, gulls endure the many ill-effects of enjoying one drink too many. Or, as RSPCA officer Clara Scully put it, “They’ve really been suffering with hangovers after a gulls’ night out.”