When we first developed the Hawk Eye with its infrared night vision, we talked to the good folks at the National Audubon and Cornell Ornithology Lab and were assured that 1) just like us, birds can not see infrared light and 2) such light does not in any way bother birds.
The Hawk Eye Nature Cams come equipped with six to 10 infrared diodes, surrounding the lens. These give off invisible infrared light. Unlike some infrared lights our diodes do not glow red. There is no way to visually tell that they are on. The only way to tell is to plug the camera into a TV, and then put it in a dark drawer, or cup your hand over the camera. You will see a white glow on the TV screen which is the IR light reflecting off your hand.