A "flock" of crows is called a "murder of crows", not a flock. No idea why. However, a group of Baboons is called a "Congress of Baboons", which makes a lot more sense, and we don't even have to wonder why. I'd assume that a murder of crows or a congress of baboons would be three or more, but I don't have any facts to back that up. I'm sure Google would, tho. I'd have to ask if a group of Canadian Baboons would be called a "Parliament of Baboons", except that they don't have many of them.