Pokemon Generation Habitats aka Pokemon Darwinism
For a demonstration I will use the common Bird Pokemon Niche
gen one kanto PIDGEY = on the ground in the sun on the plains is chubby good at running away from its predators and ambushing its prey
gen two HOOTHOOT = in the trees has large eyes and is nocturnal with a tiny beak and has rear limbs like clock hands and even has a clocklike body
gen three TAILLOW = its on an ilsand has broad and narrow wings for catching island currents
gen four STARLY = up on a high mountaintop, its all in literally black and white for its plumage
gen five PIDOVE = evolved around a city like structure, most likely, Castelia city with humans ergo its gray and stone like
gen six FLETCHLING = is bult for france and nordic territory, has a red head and grayish body and is even tinier in size as compared to the gen one Pidgey
gen seven PICKIPIECK = a woodpecker for a tropical environment the heat surface area to mass ratio fits pikipeck perfectly