It's been longer than I'd like to admit since I cleaned the windows of my apartment, and this morning I got up and pulled aside some of the ivy from a window in my living room, getting ready to do some cleaning, and exposed a bird's nest with two eggs. The bird showed up a few minutes later (photos below the cut). She's brown, not grey, doesn't have the usual stripes, and is not as big as the pigeons you see on the street, so I'm not sure what she is. But she's a great excuse to leave the windows dirty!
UPDATE: Sad to say, as of Tuesday morning, the bird, both eggs, and the nest are gone.