This year, the fledgling is spending most of its time on St. Luke's Hospital rather than on St. John the Divine.
The current father arrived when the Cathedral roof construction was in full swing, so he naturally perched on St. Luke's rather than St. John. The father's favorite perch on St. Luke's also has a view of the large green at Columbia University, which had been home one winter to a young hawk. I think this switch in behavior by the father, is influencing the young fledgling to perch St. Luke's.
Below are pictures of the fledgling's first full day off the nest. A pair of Kestrel's have been harassing the parents on St. Luke's and are included in set of pictures.