The bird needs to go to a vet and get anitbiotics for the cat bite ASAP. You did say the bird had bite marks on it. More times than not a bird will die without antibiotics because cats saliva has bacteria that will kill the bird. Some vets will do what is needed at no cost to you for wildlife so look and call around to find one.
I dont know what kind of bird it is but it looks to be a fledgling. It was prolly out learning to fly and honing it's skills when the cat came along. It will find and eat food on it's own at this stage. You can keep it in a box and place worms, crickets and seed in there with it. Give it a shallow bowl of water in the box also.
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If rabbits feet are so lucky.....
What happened to the rabbit?
