I went up to Inwood Hill Park, in addition to Highbridge yesterday. Although the female was sitting much higher on the nest, I didn't see any baby hawks. Neither did Robert B. Schmunk who was up there at the same time.
On Saturday evening, I saw that Alice Danna had also been up to Inwood Hill Park (but earlier in the day), and had seen two eyasses with one of the rangers (via Donna Browne's Palemaleirregulars blog.)
So, I gave it a second try on Sunday and was able to confirm Alice's report. I didn't see two eyasses, but the mother's behavior would make me believe that there was more than the one eyas.
This makes the two "old school" tree nests in Manhattan a success, while we don't yet know the fate of the three "new school" building nests, 5th Avenue, St. John the Divine and 888 7th Avenue. So the current score is Old School 2 - New School ?.
Below are pictures of the Inwood Hill Park female and her eyas(ses?) There would be no sign of an eyas and then a head would pop up for a few seconds. It was impossible to tell if it was the same eyas or multiple eyasses.