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.
Body found in Bideford fire investigation
Three teenagers currently on bail
Royal Clarence Hotel redevelopment to start
Work to start on historic city centre building
Road closures for Tar Barrels event
Organisers list road closures and residents-only access.
More redundancies at Devon shipbuilder
Redundancies could include managerial roles.
Devon's fire service change alarm response
Changes could save hundreds of thousands of pounds.
Exeter woman averts disaster at Greek airport
Exeter woman hailed 'a hero'.
