A very rare winter visitor to this area; they are uncommon migrants in spring and fall. It should be wintering in the Caribbean, Central America, or northern South America.
Found a day or two earlier by another birder.
Seen along the George Washington bike trail between Belle Haven picnic area and the 8-mile marker.
Oreothlypis peregrina. Belle Haven area, Fairfax County, VA 27 January 2013