The three birds are a Pigeot and two Fearows who sought ultimate power, and evolved into their current forms. Others have evolved into such forms as well.
>>32011502
that's a pretty autistic headcanon OP
>>32011528
I know, right? My headcanon for Groudon is that it's a Pokemon living in the mantle. I think its Primal Forme is the form that it takes in the mantle.