Doggie 3 is another English Cocker. I'm doing what I can to make him a scent hunter rather than a sight hunter.
Doggie 1 used his nose more than his eyes. He was methodical and often found birds that other dogs ran by. He'd mark a bird down then go put his nose on the ground to try and find it for the retrieve. One could saunter behind him at a gentlemanly pace. He paid attention to where I was and rarely hunted more than ~20-25yds out. He knew in open prairie like hunting sharptails that ranging out a bit and covering more ground was OK. And, he knew that when hunting thick cover, he needed to be more methodical, cover the ground well and hunt closer.
Doggie 2 used his eyes more than doggie 1 and wasn't really whistle-trained. Doggie 2 would jump into cover where he saw a downed bird fall, then hop around trying to flush the bird again rather than putting his nose down and picking up the bird. Not always, but, often enough that it was annoying. Doggie 2 took more "management" than doggie 1 did.
Both 1 and 2 also completed some in-cattail retrieves I didn't expect them to make. Both 1 and 2 occasionally got on running birds, lost their mind and lined out for flushes that were WAY out of range. In both cases, they were an asset to the hunt rather than a detriment/hindrance.
It's too early to tell how #3 will turn out. I'm letting him slow down to work out anything he smells that excites him. As he gets older and more experienced I'm hoping he stops getting "birdy" on things like mice, squirrels, and frogs. :;:huh So, I'm encouraging the nose use and so far what he sees hasn't been an issue with the exception of a jackrabbit that flushed @ my toenails. When he came back after chasing the rabbit I hooked him up on the short-leash attached to my belt until we got to the next bit of cover I wanted him to work.
If I have to introduce the collar this fall, I will. But, I want him wearing it a bit 1st so that the collar itself isn't the ultimate reason that he listens or he doesn't.