My Vizsla did and still does that occasionally. He is now almost 4 yrs old. I don't really see it as a problem for my dog. He most certainly knows the difference in both birds, and once he gets birdie on a Pheasant, Quail or Chukar, it is obvious what he thinks he should be doing. While he was a pup, I never stopped him from chasing or pointing anything other than four legged creatures. If it flew, (including grasshoppers, moths and butterflies) I would give him the whoa, and he was pointing all of them at an early age. I would be very cautious about using an e-collar when trying to control him against any type of bird. All dogs take an e-collar very seriously , and I would be concerned you may be teaching him that it is not good to chase anything that flies, including game birds. I too, use an e-collar, but mainly for the dogs safety and not to chase the four legged animals. At your dogs age, I would just verbally repremand him against the tweeties and encourage him when on game birds. I have to believe he will figure it out with time.....a lot of time on game birds.
Just my 2 cents worth. I hope this helps.
Paul