I've heard a lot about the drone. He was a normal falcon for ages, he got bit not long after I got the shield. Apparently it presents differently in birds.
I didn't even choose most of mine. Shredder was Kamala's, she's one of my trainee Avengers. Lulu was given to me as an egg by Selene and Lillie who I used to look after, and the two budgies were confiscated from a hoarder.