Visits to the corner of Morningside and 113th from Wednesday through Friday resulted in... Wednesday, a glimpse of the Isolde in the nest, perhaps rotating eggs. Thursday, nothing. Friday, the new male flying up and down Morningside Drive and a glimpse of Isolde in the nest.
As the light dimmed on a dreary Friday evening, Isolde's head was just barely visible several times.
It's been five weeks to the day since the first report that Isolde might be brooding in the nest. So maybe an egg has now hatched. And maybe not. A clear sight of feeding behavior is needed.