hot cars killing dogs is a knowledge-issue, not an intelligence-issue. to put it together on your own:
you need to know cars in the sun get really warm, you can accidentally avoid learning that by moving from somewhere cold to somewhere warm during winter.
you need to know dogs are among animals that are hurt by being really warm, which you could avoid learning if you're used to something that handles heat really well like short-haired cats or camels or tropical parrots.
birds need calcium, it's obvious whether you should give them milk or not.
just in case, it's obvious you shouldn't. birds are lactose-intolerant, because they're birds and not mammals. it's not immediately lethal or anything, at least not in small amounts, it just upsets their stomach.