Just saw a new ability in the tournament. If the monster eats ‘obsidian grubs’ then you will gain the perk ‘friendly birds’ where birds will not scatter as you run by.
So actually there was a post from a dev which explained perks.
There are some “special” wildlife, with the same stats and life but with a white skin. If you kill one of them and get/touch/grab the bonus, you will get a perk depending on which creature it was.
(or maybe a semi-random perk)
Friendly birds if one of these perk and basically it prevents you from scaring birds, or having harpis (other kind of birds…) on corpses after eating.