What does a bird dog actually scent?

[Fishook]

In your opinion, what does a hunting dog actually smell or scent when bird hunting? I have been told (a)the dog actually smells the birds breath, (b)the bird actually emits an odor from scent pouches and ©the birds feet emit the scent. Guess I am not real sure. Just curious.

[MikeYager - Suzuki]

Good question. I notice my dog does not get hot on a scent I just shot the bird from. As young as she is I doubt she is that smart yet.

[gspman]

Although not scientifically proven, the theory is that a dog will work both a birds breath, and their body scent. If a dog is working with a high head they are searching for breath. If their head is down they are working body scent.

[Bushwacker]

I have really noticed with my lab that she smells living birds about 10 times better than she does dead birds. It is her first year hunting so I have taken her out a lot on her own and just let her lead where we go. She picks up on a scent from great distances away. I just follow her to where she leads and she flushes a bird almost everytime she gets "birdy" on a scent. The thing is, when I shoot a rooster dead in the air and it lands in cover, she has a little trouble finding the bird. She has found everyone that I have shot, but sometimes it takes a couple minutes and she is only starting 20 feet away in the first place. I guess I never thought that it could be the breath, but that would make a lot of "scents"(sorry, but who could resist)