I just saw a male Magnolia Warbler (additional link) in our neighbor's apple tree early this evening, just before dusk. He was darting around the tips of the branches. He looked like he was foraging for insects among the leaves.
Because he was at the ends of the branches, instead of the interior, and because I was watching him from our upstairs back porch, I was just a few feet away. I got several good looks at all sides of him, so I'm confident of the identification.
I've seen them before, at our old place in Park Slope. This is the first I've seen one at our new house. They're beautiful birds.