Assuming the bird was not trapped, brought here illegally as a cage bird, and subsequently escaped, it's astonishing that it wound up so far from home. This species doesn't really migrate except altitudinally (from higher elevations in the mountains to lower elevations), and has only been recorded anywhere else in the U.S. just a couple of times, those sightings all being close to the Mexican border.
Nevertheless, here it is. It's been visiting the feeder near Reading, PA for several weeks now, it's been seen by hundreds of observers, and a news team drove two hours from Philadelphia to do a report on it for the evening news.
The bird is a black-backed oriole and the icing on the cake is that, like most orioles, it's a gorgeous creature. Unfortunately, the picture doesn't do it justice:
