What do i feed new born moking bird ?

what do i feed a newly hatched mocking bird ? i was walking down a street with some friends we seen a nest all torn up in the middle of the street so we picked the eggs up and took it to the house. One of them hatched already and it's sqwaking and i think it's hungry i cant take it to the vet or bring it back to the nest cause it was on the ground torn up ! So if anyone can help me find out what to feed itthat would be GREAT please and thank you !