That's a hard way to wing clip a bird. I amputated the right wing off a teal one year. Bird land within five yards of the blind. Swam around like it was just confused. Tried to take off with only one wing. Other wing was floating a few feet away. Kind of a weird sight.
It's a tribute to how good your dog is to have recovered that bird. Sometimes the dog knows more than we do when he wants to go where his nose tells him and we want to send him where our eyes tell us that bird must still be. Hard to listen to a dog for some of us.