Our wonderful springer spaniel, Bill, got his limit far faster than any other hunter because he always found birds downed by other hunters and dutifully brought them to Dad. I would never, but never, run to pick up a bird. Our diminutive Springer, Lady, was known to do the same thing. Once, when duck hunting, she jumped into the water, swam around some reeds and came back with a wounded duck. No one in the area had fired a shot. Same with winged pheasants that couldn't fly, but could still run and "spur".
Funny -- the first time my little Lab got live fliers, a friend of mine just grazed a mallard hen. When my girl got to her, she was HOPPING mad. The Shell grabbed the duck, shut her eyes, and came charging back with the hen pecking at her and beating her in the face with her wing bones. She came to heel like a shot -- "PLEASE take this bumper right away -- it's not behaving!"
Somehow it didn't put her off at all - she still goes after them like gangbusters.