Wattrel and Kilowattrel

Squawkabilly was unusual in being an early game bird that never evolves, while the first realistic multi-stage bird in Paldea comes a little later in its dex. Wattrel is an electric/flying petrel, a term that can actually refer to two unrelated but outwardly very similar groups of seabirds. It's a nice, solid design for its role, with very large, circular eyes that give it a cute and comical quality. It's the first Pokemon to come with the ability "Wind Power," which boosts electric-type attacks under the effect of Tailwind or when the Pokemon is hit by any wind-themed move, and this tells you the rationale behind it's electrical typing; it uses wind energy to build up electricity, and according to the dex, discharges it when it dives into the ocean to stun aquatic prey! I really like that! Nice speculative ecology!

Wattrel evolves into Kilowattrel, Pokemon's first frigatebird! These seabirds are renowned for how long they can stay aloft at sea, around two months at a time without having to land. That's not the record for any known bird, but it's still not terribly common and it's especially impressive for these duck-sized fish eaters. They're also famous for the huge, red, inflatable throat sac the males use to attract a mate, but both sexes of Kilowattrel have a giant yellow sac for storing even more of their collected energy! The rest of the body is black, and the sharply swooping wings are also black and yellow, with jagged edges and borders throughout the design to communicate its electrical nature.

It's a fine choice of animal to drop almost directly into the setting, and electric typing is a surprise that nonetheless suits it well, in my opinion.