RE: What kind of duck did i shoot.
certain ducks have certain wingbeats, some have distinctive "air cutting" sounds as they pass overhead, the speculum of thier wing is different, etc.
Really, no one should confuse a teal with a black or a mallard, a mallard could eat a teal!
Ny law allows 4 mallards as part of the dailybag limit, no more than 2 of which may be hens. hen mallards look alot like blacks, but blacks are generally bigger.
i'm sure you could google "waterfowl ID" and get good answers.
shoot the wrong bird, too many of one kind, wrong sex, etc and the "wrong " game warden will crucify you, they dont want to hear excuses.
you'll pick it up if you are serious about it, good luck!