The safest way to guess whether a bird is "protected" or not, almost 100% of the time, if it doesn't have a hunting season on it, or isn't considered "eatable", it is probably protected. As to the bird-world being smart? I blasted my 12ga, O/O buck, along side both merganzers and cormorants, and they would just sit there and look at me until I walked towards them. How I rememdied that is still classified, but "simulated movement in a blind" after getting their (serious) attention works well.
