Snowy Egrets vibrate their feet in shallow water to scare prey (crawdads, minnows, tadpoles, small fish) and make them move. That's a wicked looking beak on the Snowy below.
When I worked with wildlife rescue I learned oretty quick to cover the head on any egret or heron first, when they get scared they go right for your eyes. A beak in the eye could kill you, sure would take an eye out. I lost several good shirts if that is all I happened to have to throw over them.