Pidgey, Pidgeotto and Pidgeot may be birds, but they’re not exactly Legendary. However, this little known fact hasn’t stopped a number of Pokémon GO players from disguising the trio as the Legendary bird Pokémon Moltres, Articuno and Zapdos – all three of which are extremely rare and can only be caught for a limited time.
https://twitter.com/ImPinkt/status/891171191720988672
Source: Kat – MsPinkt