Tuesday, March 20, 2012

Waiting for Egg #3

Following the excitement of the second egg's arrival on Saturday, the formel appeared more tired and lethargic than on Wednesday with the first egg, when she more or less bounced in, laid the egg, and headed out.

She spent most of this weekend sitting on her eggs,

... occasionally getting up to turn them,

... and settling back down again.

I checked in with John Blakeman about the difference in her behavior and he commented:

"Her lethargy with the second egg is to be expected. Producing the first egg wasn't overly stressful, as she had full, yet-untapped resources to accomplish this, but the second egg came from reduced protein, calcium, and fat reserves.  She loses a lot of serum-mobilized fats, proteins, and some carbohydrates, along with an egg-full of plain water in the production of each of those first two eggs. Producing a third egg will be even more stressful, both physiologically and psychologically. The restraining results of this last "eggnancy" should be apparent. 

But she will be well. She's done this all before, so successfully. She's being well provided for by the tiercel. She will recover in a week's feeding and rest in the first full week of real incubation. Right now, she's not sitting tightly. She hasn't begun full, coordinated, irrevocable incubation. That will commence with the third egg."
--John Blakeman

But the formel does get up to stretch and spend some time away from the nest.  Sometimes, the eggs are left on their own for several minutes, which is not a problem as they can be left uncovered for up to 20 minutes or more.

The tiercel also loves to take his turn on the eggs.

It can be quite difficult to tell the difference between mom and dad when they are on the nest. Here are pictures of each bird sitting in an almost identical spot on the nest



At night, however, it is the formel who settles onto the nest and stays till dawn.

It perhaps seems unusual that the tiercel is so involved in sitting on the eggs in these early days while we await the arrival of the third egg.  Last year, John Blakeman shared some fascinating insight into the psychology of the hawks at this crucial time of egg laying:

"The tiercel's lengthy sitting upon the eggs (but it's not incubating yet at this early stage with another egg yet to come) is of no concern. Neither bird is yet in full incubation mode, especially the female. She almost surely has a third egg growing and descending her fallopian tube. Producing a third egg is particularly demanding, both physiologically and psychologically. 
Frankly, she's just in no mood to be sitting around on the nest on eggs. It may be far more comfortable to be standing, to allow gravity to assist in the flow of the new, last egg down the fallopian tube. She's eager to get that last egg formed and laid. When that happens, when she's relieved of the stress of egg formation, everything will change. Incubation will begin in earnest, with a profound compulsion by the formel to sit tightly and convey lots of body heat to the eggs across her naked brood patch under the feathers of her belly.
The tiercel, like fathers everywhere, just scratches his head trying to figure out the anomalous behaviors of his "eggnant" mate. Dutifully, he sits over the eggs and protects them. He'll be relieved when he can head off each morning to hunt for both his mate and himself. He really wants to be out there hunting and killing things for his mate. And his mate will have a tremendous compulsion to stay on the nest and begin another year incubating eggs and raising eyasses."
--John Blakeman

But for today, as we wait hopefully for a third egg, both hawks took their turn on the nest.  Here's dad...

... and here's mom.  Her wings often hang a little lower along her body, revealing that distinctive white line down the middle of her tail, more noticeable than dad's.

 Here is a sequence from today of her standing up to stretch a little...

... then preen her feathers.

Suddenly, there was a headless hawk as she reached way underneath herself to start rolling the eggs.

 As she rotated the eggs, she moved around them...

... until she had them where she wanted them,

... and then settled back down,

 ... looking out on the blazing March sun we enjoyed today in Philadelphia.

If all goes to the schedule - as it has for the past three years - the third egg should arrive on Tuesday, sometime in the middle of the day.

1 comment:

  1. Sunny, it's interesting what John Blakeman says about how much more stressful it is for the formel to lay the 3rd egg. Those of us who saw her lay the 3rd egg today noticed how she was breathing heavily when she was done (although we weren't positive she had actually laid the egg at the time). Now she has to rest up for the time the eggs hatch and her "triplets" need so much attention.