Pidgeotto-Pidgeot
Ash never caught Pidgey, he caught it in it's second stage of evolution, Pidgeotto so i won't comment on that. Pidgeotto proves to be pretty strong. Some of Pidgeotto/s common attacks seen in the show are sand attack and gust. It often uses it's gust attack to clear dust or smoke from Jame's Koffing/Weezing.
When Ash's Pidgeotto evolved into Pidgeot, Pidegeot left with all the other Pidgey, Pidgeotto and Pidgeot I think that Pidgeot will return one day I hope.