3/17, Switch-Off!

As experienced hawkwatchers know, if it's March and you catch a pair of hawks switching places at the nesting site, it can only mean one thing. Eggses!

But first...

On St. Patrick's Day, it seemed quiet near the cathedral nest area before sunset. But at 6:40 as I began to leave, a hawk popped out of the nest area flying north. Much like Tuesday last week, it landed briefly atop the Scrymser Pavilion at St. Luke's Hospital, then flew on to the roof of 44 Morningside Drive. Atop #44, it started chowing down. The prey appeared to be a rat, but apparently not a huge one, as dinner was over in less than ten minutes. Then the hawk spent a few moments looking around.

Initially I thought it was Norman up there, but hmmm, some of the pictures suggested a brood patch in the middle of the breast. A better view of the hawk's shoulders would have helped.

In any event, about 6:50, the hawk headed back toward the cathedral. It stopped briefly atop the Plant Pavilion at the hospital, but as I caught up, it moved on. From a distance, it seemed as if it had gone into the nest site.

A minute later I realized that a hawk — the same hawk? — was preening atop the cross on St. Savior Chapel, below the nest. This hawk then flew over to the roof of the Minturn Pavilion at the hospital and perched for a couple minutes, catching a bit of the sunset light coming down 113th St.

Finally just before sunset, the hawk in view flew over to the nest, joining the other cathedral red-tail. They "conversed" briefly.

A half minute later the hawk who had been in the nest took off, completing a switch-off, and headed north.

In retrospect, it seems Isolde had taken a 20-minute break from the nest to have dinner, leaving Norman to cover the eggs. At 7:00 she returned, and he left to roost for the night.

This isn't the sort of activity you'd see when there are no eggs in the nest, so it looks like some time in the past week, Isolde has laid her clutch and started brooding.

Incubation for red-tails takes about 30 days, plus or minus. (Isolde spend about 31 days brooding in 2007.) This suggests the hatch "window" will open the weekend of April 10, and close a week or so later. This would be a week or more earlier than in past years for Isolde, but word is that at least two other red-tail nests in the city have also had their mothers start incubating early this year.