The Pittsburgh Pirates are making headlines because they're in the baseball post-season (vs. the St. Louis Cardinals) for the first time since 1979. They make for a good story, but here's what isn't good: all the sportscasters who insist on referring to the Pirates as "the Bucos."
No one uses that word in real life. It's like "lavatory" on a plane -- we call it a bathroom everywhere else (except kindergarten). I know that the word comes from "buccaneers," a nickname for pirates, but I have never heard a civilian (i.e. a non-broadcaster or non-sportswriter) say, "I'm going to watch the Cards-Bucos game." Besides, there's been an NFL team named the Buccaneers for several decades, and you'd never refer to them as the Tampa Bay Pirates. So knock it off!