It's not fully feathered?
EEK!

How often have you been feding this bird? You need to contact a wild rehabilitation center for them to help you feed this bird. If this bird is less than a few weeks old (which is very likely), you'll need to go out and buy handrearing formula and feed anywhere from a few minutes to a few hours. Try to locate the crop on this bird; it's like this balloon-like thing right in front of the bird's throat. When the bird is "full", the crop will become large and round. Just like your stomach, the crop will empty every so often. Once the crop is ALMOST empty (NEVER let the crop go completely empty), feed the bird with the handrearing formula. Make sure the handfeeding formula is warm, not hot! And continue to feed the bird little insects and worms. Can you tell me what kind of feathers the bird has? Are they fluffy? Or are they sleek-looking, like an adult bird? I'm *hoping* this poor thing was just plucked and actually is fully feathered, but I need you to answer this for me

As was mentioned before, keep this bird warm! Since wild birds can tolerate much colder temperatures, anywhere from 80-90* F is good. But I would suggest you place the bird in a clean plastic aquarium and place a heating pad underneath one side of the aquarium. This way, if it gets too hot, the bird can waddle to the unheated side of the aquarium. Baby birds are very precious and I'm anxious to know if it survived the night...*cross my fingers*

Edit to add: You can find Lafeber's Handfeeding Formula in any PetSmart. In the meantime, please contact a wildlife rehab center.