The hawk nest at the north end of Highbridge Park, near the intersection of Dyckman St. and the Harlem River Dr., is a pain in the neck to watch. It's up in a tree in the woods and alongside a steep, rocky slope. Good sight lines you find at the start of spring are wiped out come mid May when the foliage has grown in. Which is all to say, I know there's a red-tailed hawk nestling up there. I'm just not sure whether there's another.
One nestling was plainly visible when I checked on the Highbridge nest Sunday afternoon, even if he wasn't sitting very high. Eventually he sat up just enough to get a good look back at me.
There was another spot a foot or foot and a half to the left where something pale was visible through the nest sticks, and at one point there was a spate of movement there that lasted 5 or 6 seconds. Just enough to suggest the presence of a second nestling, but not enough to be sure.