I call the place where the three are now, the "edge", as in edge of the nextbox. I think that White is on the "ledge" which runs alongside the nestbox and where all four will probably end up. That's likely where they will "launch" themselves from.
Listen to me! As though I have the slightest idea of what I'm talking about! Really, I'm just guessing...
It does look like a head behind that blur on the lens...but it's not moving, so I'm thinking not...
Someone just jumped back into the box.