One for birds, because they are extremely loud and distracting on some reserves, particularly any time you are not hunting them. They're loud enough and the sound queue will block or override the other animals in an area, a serious annoyance for hunting anything in thick brush where you rely on sound to locate the animal you're stalking.
One for the ATV, think somebody stole the muffler off that thing, might wanna report it to the wardens. Seriously it is loud enough to cause migraines and a lot missions require extensive travel that would take hours without the ATV.
This is more focused on Quality of Life than anything and we don't expect you to change much of anything in game just give us the option to tone down the sounds that tend to cause headaches, please.