Bird Pokémon are a large and diverse group, part of the larger Dinosaur Pokémon group. Bird Pokémon evolved the ability to fly naturally during the Jurassic period, and diversificated greatly after the Cretaceous extinction, when Pterosaur Pokémon such as Aerodactyl died off, leaving an important ecological niche free.

This group includes very derived forms such as Lugia (Lugium oceanicus) perfectly adapted for a fully aquatic lifestyle and unable to fly naturally, Blaziken (Torchicus blazeus) a species that traded fully formed wings for developed arms, and Skarmory (Skarmoris bladewingium) with their metal covering.

The relationship of the entire group is still controversial, especially for peculiar species like the ones cited before, but new paleontological discoveries might shade some light on the matter.

Speaking o which, a new species of Bird Pokémon part of the Bird of Prey Pokémon group, was just described from several fossil remains dated around 6 million years ago from Argentina. This species has been described as one of the largest Bird Pokémon ever discovered, almost rivaling Ho-oh (Hoohis rainbowii) one of the largest Bird Pokémon known.

Argenterror (Argentikus largewingium) was a formidable predator, biomechanical studies show that its beak and talons were extremely powerful, and were probably used to catch even large preys in a quick swoop. It is currently unknown if all the remains found are from the same individual, but all of them show signs of serious injuries that seem to have healed, and most of them seems to have been caused by other Argenterror. This has been interpreted as interspecific fighting, which implies that Argenterror was a very territorial creature, fighting anyone who enters its territory.