In terms of dangerous animals, I have seen Moose, coyotes, and snakes.
I do have to say, though, that the only animal (or in this case, bird) that has ever made me worried has to be the vultures. They stare down at you with their beady little eyes and all of their heads turn in unison as you pass under them, and you know that they are just waiting for you to trip and fall...it is very disconcerting.