In my experience, anything that's appropriate to the planet is suitable, whether or not it has anything to do with the assistance you're asking for. With Mercury, I tend to make donations to a charity that helps children with speech, language, and reading issues -- that seems to work pretty consistently. In the same way, you can certainly donate to a Mars animal charity; aside from the ones you've mentioned, wolves are Martial, and so are all birds of prey, so a raptor rehabilitation center would be a great choice, and so would be a wolf charity.