There might be reaction from movement, but what about a double bull blind, where they cant see a thing.
I think it's sound my friend.
Speed of sound:
Sound is a vibration that travels through an elastic medium as a wave. The speed of sound describes how far this wave travels in a given amount of time. In dry air at 20 °C (68 °F), the speed of sound is 343 meters per second (1,125 ft/s). This equates to 1,236 kilometers per hour (768 mph), or about one mile in five seconds.
The animal hears your bow and or the arrow flying through the air ( so fast they could smoke a cigarette and still beat your arrow. lol) that's 37.5 yards in one tenth of a second, your arrow has only moved 6 yards in one tenth of a second( if your shooting 180fps )long before the arrow get's there.
I have stood behind a brick wall( to be safe ) with my friend shooting about 30 yards to a target past me about 5 yards, not only could I hear the vibration of the limbs, ( I could not hear the string ) I could hear the arrow coming the whole way, slow, vary slow compared to sound.
Just my 2 cent's