3/19, Brooding

The last two days provided evidence of red-tail mamas brooding eggs at two Manhattan nests.

Friday at the Cathedral of St. John the Divine was almost quiet, but every now and then I could see the tips of some tail feathers wiggling above the edge of the nest, and once Isolde poked her head just high enough that I could see her face. It seemed like she was really and truly hunkered down on some eggs. Sure enough, earlier in the day, James had managed to get a picture of a switch-off as she and Norman briefly traded egg-warming duties.

Late Saturday afternoon, I headed up to Dyckman St. to see if the Highbridge Park-Swindler Cove red-tail nest was still there after the nasty rain storm a week ago (I had found it in good shape back in February) and whether Martha might be brooding, too. Barely had I arrived there than there was a switch-off. Apparently Martha was returning from a rest and/or dinner break and took back over from George. She stayed put, with only her head to sometimes be seen during the next 45 minutes.

Elsewhere, Bruce found the Riverside Park Boat Basin mama hawk brooding last Monday. The 2011 nesting season is under way, and baby hawks should be hatching hatch between April 11 and 20.

3/17, Eggs Imminent? Or Already?

I'm beginning to suspect Isolde is very close to laying an egg, if she hasn't laid the first one already.

Early this evening the nest looked empty, but a bit later I noticed a couple tail feathers poking up on one side and wiggling around. Then all was quiet for the next ten or twelve minutes. Around 6:25, Isolde sat up and started watching the skies to the south and east.

She sat like that for over 15 minutes, and one began to suspect she was feeling the hungries and was wondering where Norman was with her dinner.

About 6:45 Norman whizzed by and Isolde immediately popped out of the nest. Perhaps there was a bit of miscommunication as to where food was supposed to be delivered, as the pair perched on opposite sides of the hospital roof. But quickly enough things got sorted out and both hawks perched on the corner of the roof at 54 Morningside Drive, the same spot where Isolde had her short dinner yesterday.

Over the next five minutes, Isolde chowed down on a rat, while Norman watched.

Then Norman got bored and took off. But Isolde must have been starved, as she spent another ten minutes eating.

A few minutes after 7:00, Isolde finished up and headed back to the nest. Along the way she stopped for a minute to scrape the schmutz off her beak on a corner of the roof at St. Luke's.

That Isolde was lying down in the nest for some time is suggestive of an egg having been laid. But that she was willing to sit up for 15 minutes, and then leave the nest empty for another 15 means she isn't obsessive about incubating it yet. That would hint that she hasn't finished laying her clutch.

Or perhaps I'm just reading too much into her behavior. Nevertheless, it did look like she was going to spend the night in the nest, and that's usually a good sign that egg-laying is imminent.

3/16, Almost Nesting Time on Morningside

Early this evening, Isolde of the Cathedral of St. John Divine red-tailed hawks was hanging about her nest, watching the skies and perhaps enjoying the clear air (after a rainy morning). The amount of time she spent just sitting there suggests that egg-laying time is approaching, but that she was sitting rather than laying down in the nest indicates she hasn't done so yet.

A couple minutes after 6:00 she perked up and stepped out on the north side of the nest. She flew across the street, perched on the roof of the hospital for a minute and then took off northward again. I found her perched with her mate, Norman, on the roof of 54 Morningside Drive, at the corner of 116th St.

Apparently a food delivery had been made, as Norman took off a few seconds later.

And flew down to the hospital where he perched for a moment.

Meanwhile, Isolde had started chowing down.

Can't quite tell what it is yet.

She stopped eating after just a few minutes. Gave me and another hawkwatcher the hairy eyeball.

Maybe had another peck or two then stood up and looked around. Then back into the air, flying south along MSD.

Ah, dinner was a rat, and apparently she just wasn't hungry enough to consume it all in one sitting.

And back to sit around the nest some more.

In case you're wondering when Isolde will lay her eggs and when a hatch would occur, well, all we can do is guess based on what happened in prior years. Keep in mind that incubation takes 28 to 32 days.

In 2010, we know she had laid egg(s) and was incubating by March 17, and that a hatch occurred between April 13 and 18. However, last year was the earliest we'd seen this, by a week or more.

In 2009, Isolde apparently did not use the cathedral nest. Or possibly there was a very early nest failure and she and Norman did not try for a second clutch. This was right at the end of the cathedral's repair project and the hawks might still have been stressed and behaving oddly.

In 2008, egg-laying did not occur until after the first of April. That was also the year when she lost her prior mate, Tristan, and then the cathedral erected scaffolding all around the nest area, so things were pretty disrupted.

In 2007, egg-laying occurred about March 23-25 and hatch before April 27. No one was observing in 2006, but other evidence sugests it was roughly the same as 2007.

So... best guess is that egg-laying will occur next week.