Wednesday, April 14, 2010

Our tiercel is working hard these days!

As the hatching of the eggs gets closer, the tiercel (male) is working increasingly hard to meet the needs of his mate who is doing the majority of the incubation.

John Blakeman shares this fascinating information about how the tiercel and the formel accomplish the tasks necessary to successfully hatch their eggs:

"The smaller tiercel now has his work cut out for him. During incubation, the formel feels tied to her eggs, keeping them warm. She can no longer head out and sit in a tree waiting at length for a prey animal to scurry by. She’s stuck in the nest for perhaps two or three more weeks of marked nest attachment.

Her days of motherly confinement to the immediate nest area will terminate about two weeks or so after hatching, when the eyasses get big enough to stay warm by themselves during the day.
Then, the formel will head off and be absent from the nest for perhaps hours. She will be out hunting like the tiercel, striving to provide ample food for the rapidly growing eyasses.

But for now, the tiercel must now provide food for both himself and his mate. And she’s bigger, too, requiring more food than he does. So his duties are more than doubled.

But he’s a male, and we all know how males like to go out on the hunt. He’s doing this now for his appreciative mate. His testosterone-induced behaviors must now be diverted from nest-building and copulating to a full day’s worth of hunting, killing, and retrieving of prey. Everything depends on him, on his ability to keep his formel sated and seated. If she gets too hungry, she’ll get up off the eggs and in hunger go out and hunt for herself.

But our tiercel was a great provider last year, and will be this year, too.

Then, there is the matter of egg turning during incubation. Before real incubation began, the eggs were left to sit there essentially as they were laid. Now, both parents will feel obligated to stand up a bit, hovering over the eggs, and bend down and push the eggs around the bowl of the nest with their bills. It looks like they are practicing a bad game of soccer with the eggs. Actually, they are causing the eggs to take a new position in the nest. If this isn’t done, the developing tissues and membranes in the egg fuse together and the eyass will die before it can hatch. All bird eggs must be rotated to keep things properly growing inside. So we will see both parents do this. Very important.

One other last thing. It would be romantically comforting to imagine the nest, now that it has a sitting mother with three eggs, as a cozy little nursery cottage, a warm and inviting hawk home, as it were. Not so.

The nest is not the hawk’s "home" in any human-like manner. Their home is the entire square mile or two of the territory they defend, occupy, and hunt in. Regard the nest exactly as they do, as merely an obstetric space, a place to incubate the eggs and raise the eyasses before they are fledged. The nest is not a hawk home, except perhaps to the eyasses for a few weeks before they fledge. Then, it’s just a pile of sticks. None of the hawks fly back and spend the night nostalgically in the vacant nest. It’s not a hawk residence in any such way. The parents never sleep there except to incubate eggs.

For the hawks and us, the adventure continues, now in the new chapter of incubation."

--John Blakeman


  1. Fascinating! Thank you! AnnK.

  2. thanx to all for sharing this wonder-filled world with name is Patty and I'll proudly state that I'm a hawkoholic!!!

  3. What a way to keep all of this in perspective. An obstetric space.
    Our only opportunity to watch the hawks continuously. thanks John.
    Thanks Della

  4. wonderful description- thanks to Della and John for keeping us so well informed! And the wait goes on...


  5. As this second year of "watching" continues, I am still fascinated by the world of hawks. I appreciate all the info given by John and the others,amazingly giving up their time to inform us all. Thank you, thank you, thank you! Happy watching!! <3

  6. Thank you so much!