At what point does your compassion for animals stop? I don't mean domestic animals, I mean wild ones. Personally I put the foot at the door at stuff like wild rabbits, rats, and mice.

Depends on whether or not they're attacking me or someone/something I love or not

Same with Ew. I'm fine with all of them as long as they're not hurting what I love or destroying the natural ecosystem like feral cats.

This is like the fourth conversation I've been involved in about this today, and around the eighth this week, which is an oddly high number
I only really have energy for the tl;dr version right now, which is probably all you really need anyway:
My willingness to hurt an animal starts when it puts me or someone/something else in danger (not talking normal predation situations, I'm talking attacks or gruesome/cruel scenarios). This can include pest or disease scenarios, such as mice overrunning the house, etc.
My compassion doesn't really stop. If I hurt the animal, and it's suffering, I either have to get it help, or find a way to put it out of it's misery as quickly as possible.
There's enough pain in the world already, who needs more?

I hate animals that aren't where they should be, like feral cats and cane toads. They were brought in by fukin white invaders to combat problems they created.

I hate rodents, they’re disgusting. Feral cats, I’m ok with, because they always seem to be friendly to me.

Deer

As long as they let me live in peace, I have no objections against any sort of animal. Even if they attack or annoy me, I start checking if it's maybe me who intruded their private space in the first place (in case of attack: after defense or escape).
They all have been here long before us and still will be when we're gone and they all just wanna survive somehow. And being fearsome of individual sorts like snakes, spiders or rats makes sense in some places in the world, but I'd rather try to get around them instead of killing them. Except I wanna eat them, but that's a complete other story...

To me, compassion for living creatures isn’t qualified by any specific point. I believe we should have compassion in all we do, the necessary is not always pleasant by its nature, but it doesn’t need to be any more unpleasant than it has to be. Human, plant, animal- needless cruelty or destruction isn’t an aspirational choice in any regard. Actions have consequences and we must always weigh the cost against the result- but life requires sacrifice. Reconciling that against our compassion is key to a healthy mindset.

Honestly, when it comes to animals, I don't both them unless they bother me first. When it comes to stray cats, however, I try to feed it (stupid, i know) but the cat that roams around my street belongs to a friend of the family. I don't bother rabbits at all, nor birds. I just leave them in peace.

Thank you all for your answers. I've learned new things concerning the topic.

I honestly cannot stand killing things for no reason. Even if it's a bug, if I can take a few more minutes and put it outside instead of stepping on it, I do. My dad made me kill a squirrel he had caught when I was young and since then I've been pretty opposed to killing things if I don't have to. Ending something just because it's easier for me, even if it is a bug, seems really senseless. If an animal was a threat to me or my family, or if the animal was dying or in agony, I would do what I had to do, but other than that I avoid it when I can. I don't judge people for killing bugs unless i'm already trying to get them outside, I just personally just don't like it.