One of the clearest examples of these prehistoric animals, with characteristics of birds but without turning it was the Epidendrosaurus, whose name means "lizard on the branches." It is a small theropod maniraptor (hand robber), a taxon whose main feature is the very long, curved fingers ... a feature that served to grip tree branches.
But do not think that the change from reptile to bird was linearly which followed a straight way without errors. The evolution experienced with the species, and species were able to survive for tens of thousands of years and others not, and there is almost no such evidence. But Epidendrosaurus was very successful. In fact, this prehistoric animal lived after the first birds and thousands of years after the first bird which is known Archaeopteryx, this means that even still undergoing evolution and squeezing the characteristics that conditioned the animals, even appeared almost winged reptiles and birds flying when they appeared. The few fossils has been discovered that in the legs and tail feathers had slight marks, similar to those of Microraptor (another small thief).
If we saw now, we look like a bird more than a reptile, if we looked we would see that no beak, but a tiny little mouth full of sharp little teeth and suitable for hunting small reptiles, insects and even mammals were climbing clueless the branches of the trees in late Jurassic. We seem a small bird, it is thought that it was not larger than a dove. The only bones found are young specimens and their skeletons are as big as sparrows.