While watching the LEOs (Long-eared Owls), a father and daughter came by to watch them. We got to talking and they went over the birds they had seen. One of the was a Nashville Warbler.
Now any warbler in December would be unusual, so I had to check it out. It was located just west of the North Gate House on the Reservoir. It was between the fence and the water.
Update: I got a nice note from Tom Fiore, explaining that there is a history of late Nashville Warblers in Central Park, and they've even been on few Christmas Bird Count lists.