Friday, June 12, 2009

Have feathers, will fly

Here's some more knowledgeable commentary from John Blakeman on how young hawks develop their flying skills, and why Miss Piggy had some difficulty on her first foray from the nest. John commends Rick Schubert for his expert handling of Miss P. during her capture and release.

"Some comments on the early, weak flight of the retrieved hawk [Miss Piggy]. It’s been proposed that the bird’s flight feathers were not yet long enough, or mature enough, to allow full flight, thereby causing the bird to end up weakly on the ground. The bird did have a weak landing, and it couldn't fly very well, but it didn't leave the nest too soon.

What happened with this bird is very common with rural red-tails. On the nest, the newly-feathered eyasses get antsy about flying somewhere. First, it’s just some jumping up and down with awkward wing flaps, as we saw with these birds two weeks ago. Then, the eyasses start to do short jumping flights from one side of the nest to the other, just as we saw. Next, where possible, they try to “fly” from the edge of the nest a few inches to a new branch. This nest, like many on rock ledges in the West, had no branches (not in a tree), but the window ledge worked as a landing pad for the short flights.

Finally, the birds just jump off and see how this flying thing works. And just like a little toddler tries to learn how the walking thing works, the newly-fledged (well, partially-fledged) eyass finds that flying is both wonderful and exhausting. Most of the eyasses try to quickly find a nearby tree limb to land on. But the poor little things have never been suspended out in the open air, and trying to control their flight requires neuromuscular coordination and reflexes that are yet undeveloped.

In the best of situations, the eyass is able to glide clumsily into a tree and crash land onto some branches. Often, on the first flight, the bird grabs a limb but falls over, hanging upside down. It then either tries to power itself upright onto the branch, or it finally just lets go and falls in a loose clump to the ground. There, it gathers its breath and later tries to take off and achieve a more artful landing.

That was the situation with the retrieved bird [from last Saturday]. It was all very natural, something that most red-tail eyasses have to endure in their first flights. In the rural wild, all of this happens at the edge of a woodlot or in an open meadow environment. The bird may stay grounded for a day or two, and the parents bring food to it as it clambers up into a low bush or short tree. Soon, however, the young bird figures out how to take off and land, and becomes an accomplished creature of the sky for the rest of its life.

The feathers of this bird were not too short. But as the wonderful photo showed, they had not completely emerged from the feather sheaths. That’s what the eyasses were attending to for much of each day in the last weeks. Everyone noticed (thanks to the wonderful camera) how much time the birds spent “preening,” tucking their heads down into their feathers. In fact, they were using their bills to strip off the drying feather sheaths, allowing the growing feathers beneath to emerge. For the large flight feathers, the feather sheaths still remained at the base and shank of the larger feathers, as seen in the photo.

It’s not that the flight feathers weren't long enough. They are now full-sized. But they are still, as we say, “in the blood.” As the feathers grow out, they actually have blood vessels within, nourishing the growth of these miraculous body features. So, for a while, heavy blood remains coursing through the big tail and wing feathers. Until this ends, when the bird is “hard penned,” the wings are a bit heavier. Right now, all three birds should be close to being hard penned, allowing for much better flight.

Everything that happened with the fledging of The Franklin Institute eyasses was absolutely normal for red-tailed hawks. And I commend the Institute for all that was done to let the public experience this wonderful story.

I commend Rick Schubert for his expert handling of every aspect of the capture and release of the bird.

Frankly, just everything about this entire event has worked so wonderfully. My very best to everyone in Philadelphia. Everyone there should be so proud of this exemplary red-tailed hawk family, which became so personally a part of our own."

--John Blakeman

3 comments:

  1. John, thanks for sharing your expert commentary, and for the kudos to my city and all involved in this adventure: Della for her blog, Kay for her wonderful photos, Rick Schubert for his assistance with "Miss Piggy", and of course, the Franklin Institute for making it possible to share in this experience. My heartfelt thanks to everyone.

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  2. I'll echo what Anon said, "Thanks to everyone who has made it possible for these beautiful birds to thrive in our fair city. And thanks especially to those who are lucky enough to be there to provide us with photos and explanations.

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