It was on the sidewalk, yards away from any tree. I've already taken it to the vet. They said they couldn't even take a look at it, let alone take it in for a bit, but they gave me the number of an animal rescue center that will take it. However, the center isn't open at the moment, so I have to hold on to it until they open. I've already got it set up in a box with a towel and a covered bag of warm water for it to snuggle up against, but I don't know what to feed it. The rescue directions say not to feed it, but I'm pretty sure it will die if I don't feed it before tomorrow, and definitely if I don't feed it all weekend (as the center may be closed until Monday). So I should feed it, right?

My neighbor who once rescued a baby bird fed it baby cockatiel food, but I have none of that and there are no nearby pet stores, and none further away that I could reach before they close. Is there some veg I could get and mash up that would be alright for it, or anything else? We think it's a blackbird, if that matters.