One night, when I was living in Washington, D.C., I walked up to the McPherson Square metro station and stopped for a moment to stare. There on the sidewalk, hanging around the entrance, were two ducks. I think they were together. I mean, I’m not a duck expert, but they looked quite different from each other, so I figured it was one guy duck and one girl duck. And I say hanging around because they really were at ease. More than at ease; the vibe coming off them was pretty tough, like they were letting everyone know “this is our corner, you got that?” Maybe this seems normal to you — urban duck couples “owning” the turf around public transit — but I’d never seen a duck in the city, other than in a pond, in a park, where they always seemed quite skittish. These ducks had some swagger in their waddle. I followed the pigeons’ lead and kept my distance.