Since then they have gotten smaller, lighter-colored, proteins have changted, evolved a new liver enzyme enabling them to feed on Hawaiian plants that are toxic to the Australian rock wallaby, and they do not and cannot interbreed with the original ancestral Australian species. No flowering plants are found deeper than Cretaceous rock, but ferns go all the way back to the Carboniferous, and algae far into the Precambrian. We now think that there are only 3 bird-like features and that this was mostly a reptile. In any case, it certainly was not a bird. Evolution does not work this way.
Organisms are simply well-adapted to their local environment.
An archaeopteryx is neither bird nor reptile. It is its own kind. How We Believe, and The Borderlands of Science. All rights reserved.