Tuesday, July 28, 2009

Mantling.....or share not, want not!

In my last post, I described the eyass eating the left-over squirrel and covering it with her wings to guard against her sibling sitting on a nearby pole. I called it "cloaking," but our ever-helpful John Blakeman sent me the correct term for this behavior - "mantling."

He then explained this more fully:

"The decided wing-covering of food is a well-known hawk behavior. It's called "mantling," to spread the wings out over the food, bend over, and conceal the food from the direct vision of other hawks (and humans).

I saw no mantling on the Franklin Institute nest, which meant that the eyasses there were well fed and comfortable. But as the summer progresses and each eyass becomes ever more independent, mantling may be more often observed. There is going to be a bit less "sharing," a bit less accommodation of siblings. The birds must learn to be entirely self-supporting and independent. That means they must learn to capture their own food, and also protect and use it for themselves.

So don't be surprised to see more mantling in August, as the eyasses learn to make their way in the world on their own, protecting what they've captured---all in the process of become fully independent and self-sufficient adults in the coming year.
(This image is not of one of the Franklin hawks)

The eyasses are growing up---and you are getting to watch all of this first hand, right in Philadelphia. You will continue to see less social behavior, with birds becoming more solitary and isolated. 'Tis the nature of the species. They are learning this as they mature.

The raspy, high-pitched vocalizations are typical summer-time sounds. They will begin to disappear in August, and should be gone altogether in September.

(Note from Della - I added this link to give you an idea of what the hawks sound like when we refer to that seagull-like calling:

The calls are left-over vocalization responses to hunger. There has been very little of that, but the little tykes just like to cry out for food. The sounds are intended for the haggards, to prompt them to bring over an easy meal to the eyasses, but the haggards are pretty much done with all of that.

The thing to watch is how things will change when the birds, both the eyasses and haggards, detect that the days are starting to shorten, with the sun going down earlier and rising later. Just as the lengthening days in January tend to prompt reproductive behaviors in the haggards, the shortening day lengths ---which will soon be apparent to the hawks--- will cause them to start preparing for migration and winter.

eyasses will soon be much more quiet and concentrate on hunting, not making a verbal racket. The parents will become less visible, preferring to stay in the distant background, forcing the eyasses to learn to live without any hope of parental rescue or interaction.

The eyasses may also begin to drift. Don't be surprised if you start seeing only two of them, then perhaps a single loner. Sooner or later, the migratory urge will be impressed upon them, and they will start to move the edges of their territories ever further outward. One of the eyasses might perch herself on a pediment of the Art Museum up the Parkway. Or, an eyass could start moving from tree to tree up or down the river. In the evening, it could then go to night perch there and not be seen anywhere near the Franklin Institute.

By September, all three eyasses may have disappeared. That would be very normal and typical and acceptable. None of these birds may ever been seen again in their now so familiar summer haunts.

Or, in a few cases, eyasses tend to be homebodies and they try to winter over in their natal territories. That would be so nice for the hawk watchers in Philadelphia, but it's not in the best interest of the birds themselves. They will need to learn to move on and become adults elsewhere.

Of course, that's why it would be so helpful to have had these birds color-banded, so we could tell who's who and who's where in coming seasons.

--John Blakeman


  1. Della, I would never quibble with John Blakeman, the foremost authority on Red Tails. He was there for us (Tulsa Hawk Forum) when we encountered strange, unexplained behaviors with our RTH pair, Kay and Jay.

    That said, I did a YouTube video from 6/5/09 footage that shows mantling behavior. Check it out: http://www.youtube.com/watch?v=rrzHnKRC-6Q.


  2. Fascinating, but a small part of me hopes they never go away and leave the area.