This comes from its Japanese name, Tyltalis.
Tyltalis may refer to Tyl—also known as Epsilon Draconis—a star in the
constellation Draco, the Dragon. It may also be a reference to the
play L'Oiseau Bleu (The Blue Bird) by Belgian playwright Maurice
Maeterlinck. The story is about two siblings, Mytyl and Tyltyl (ミチル
Michiru and チルチル Chiruchiru in the Japanese translation of the play),
who are tasked with finding the "blue bird of happiness."
The "Tyl" part refers to the star in the constellation Draco. Since it refers to the star in the Dragon constellation, shouldn't it be a Dragon type? o3o
Also, it looks like a bird as you say because the two siblings from the "Tal" part of its name (MyTYL and TylTYL) seek the Blue Bird of Happiness. Altaria, this blue bird, also bring happiness through its singing, as seen in its Ruby Pokedex entry:
Altaria dances and wheels through the sky among billowing, cotton-like clouds. By singing melodies in its crystal-clear voice, this Pokémon makes its listeners experience dreamy wonderment.
And it is a flying type, if it satisfies you making it look like a bird.
Either that or Game Freak tossed logic out of the window again and made it a dragon type for the lulz.