I've got pics of deer looking at camera so they must hear the noise of camera activating or reactivating.I think they hear the flash recharging.If the you have a pic of deer looking at camera the pic is done and flash is recharging??

Anyway I've got mine set for 1 minute shots and never had deer that looked spooked.Matter of fact have a few of deer nose 4-5 ft from camera. Guess it depends on camera.