Transitional Bird-Reptiles?

Footprints don't count. Many dinosaurs had a bird-like footprint and so did earlier land animals. The first birds were Juric. Convergence doesn't enter into it either, as this would involve a large number of traits. Archeopteryx, looking only at the bones, is a perfectly good small raptor. Only the presence of feathers suitable for flight gives the secret away (one skeleton now known to be Archeopteryx was originally mis-identified as a dinosaur).