Last summer we had a 5' blk snake come through the flocks yard on it's way to the coop and those birds were terrorized by that snake they know snakes are dangerous. My Muscovy duck ate a copper head when I pick up a large rock while looking for worms for them, I was panicking calling vets to see if she was going to die while she was busy going about her business,I guess eating one and being bitten by one is different.Yes they will realize it's dangerous.. and will make a lot of racket However I don't think the geese would try to attack it, however if they get bit it could be deadly