I had an injured duck come and visit me regularly along with 30 of his mates, I managed to catch him and pop him into a cat cage and take hime to the vet.
Apparently he had sprained his leg, gave him a shot of anti inflamatory and pain killers and I bought him back home.
The SPCA will pick up the bill, ring them and they will give you a case number to use at the vets, the Vet will then charge back to the SPCA.
Good Luck
Lynda