There's quite a few games that put birds everywhere down your path that shoot off when you get close. Usually crows and on something dead... They're not good for breadcruming though, because they're usually hard to make out and only trigger when the player is heading down the correct path already.
Having light spilling into the room works really well and catches the eye. Consistency in the vertical direction a player is moving also helps - so they're always going up or down in a section opposed to a mixture of the two.