Don’t know if it counts as ‘wildlife’, but last summer I totally failed to frighten a squirrel just a metre from my camera as it fired off a ten-shot burst. (I’d just set it to do that to snap a rather fast-flying kite: not the feathered kind.) It only left when it decided it wasn’t going to get fed as well as photographed.
I think I’ve only found the noise of a shutter awkward a couple of times. Once photographing two people down at the bottom of an Roman arena in France, when it really echoed round the place, and the two people turned and obviously weren’t happy at possibly being in my photo. And sometimes in a church, where it would be intrusive on people there.
Though I was talking a while back to a pro who does a lot of classical concerts who’d just got a Canon R5 so he could take photos or fire off a short burst during the performance during the quiet bits. (He was rather stuck with that, because for some unknown reason—or just cockup— the lighting director had made the violinist look like Count Dracula if she didn’t look up, and she only did that momentarily.) Something I would have liked way back when I snapped musicians more, though the Nikkormat I used for that then was quiet enough to usually go unnoticed.
BTW: we looked at some of the photos of a couple of bursts together during the interval, because I commented on the horrible ‘music hall melodrama’ lighting and wondered how he was coping, and though the violinist’s bowing had been pretty frenetic her bow wasn’t bowed. . .(Sorry.)
The squirrel is wildlife. However, wild creatures that are habituated to people (like in parks or back yards) are less skittish than creatures where they do not have constant human interaction. Can be the same species of animal but very different behaviors due to how much they see people and how skittish they are about our activity.
I shoot in a variety of locations ranging from busy city parks to rural farms and once in a while true wilderness areas. I cannot say I've had a creature run off because of my shutter sound. Usually it is because of some movement or noise I made. The shutter slap is an annoyance while my wife is with me and she is shooting video. Having click-click-click in the video kind of spoils the mood of a wildlife video.