So, out of what may have been thousands of species of dinosaurs living at the end of the Cretaceous, only three groups of neornithes had that perfect survivor's combination of being small, ground-dwelling or aquatic, and seed-eating.

因此，在生活在白垩纪末期的数千种恐龙中，只有三组新鸟具有完美的幸存者组合，即体型小、地栖或水生， 以及吃种子。