According to the Washington Post, a hawk got trapped in an escalator at the Benning Road Metro station. The article speculates that the hawk was chasing after a pigeon, which seems like a reasonable explanation. It does not identify the hawk, but Red-tailed Hawk (pictured at right) would be a good candidate to be chasing a pigeon in an urban area. Other potential pigeon-chasers would include Peregrine Falcon and possibly Cooper's Hawk. There are other common hawks in DC, such as the Red-shouldered Hawk, but if it were one of those, the explanation for what the hawk was doing in the station might need adjustment.
The good news is that rescue crews responded quickly and freed the hawk by partially dismantling the escalator. Apparently it was released on the station.