The animal welfare charity is concerned the birds have been gaining access to waste products from a local brewery or alcohol producer.
RSPCA officers have collected a number of birds exhibiting the same symptoms in recent weeks.
Birds from places such as Dawlish, Seaton, Colyton, Exmouth, Exeter, Sidmouth, Starcross and Budleigh Salterton have been treated.
Help needed to find Exminster pensioner
Concerns for Charles Fulton, 74
City lose at home again
Kyle Wooton brace gives Stockport win over sorry Exeter
Calls for inclusion on Plymouth lord mayor role
It traditionally alternates between Conservative and Labour
Upgrades to Plymouth storm overflows to take place
Hoe bathing waters are priority to stop sewage discharges
Dartmoor finances facing biggest cut for years
'Do DEFRA think the Dartmoor pixie exists?'
