Is This Big Orb the Leader of the Orb Swarm?

Photo date: September 8, 2015. Photographer: Mark Mahin.

The photo below shows the Schwarzman branch of the New York Public Library,  We see a vast swarm of orbs floating above the building. Near the left edge is a large orb that is 11 percent of the original photo height. Is this big guy the leader of the pack?

Once again, we see a strong "orb vertical bias." There is a dense swarm of orbs above the building to the right, but we can see almost no orbs in the bottom fifth of the photo or the bottom right fifth of the photo. That's not what we would see if this photo was showing natural particles floating near the camera (such particles would be randomly scattered around the photo area).

The photo above was taken at 9:00 PM. The next photo (also taken at 9:00 PM) was of a piece of cardboard at arm's length. As always, this "cardboard test" showed no orbs, indicating that what I was photographing was not any particles (such as dust, pollen, or water vapor) near the camera.

There was no fog, mist, rain or precipitation on this night. The air quality listed on airnow.gov was "good," with a rating of 50.