Tuesday, June 03, 2008

Blakeman on Eyasses Returning to the Nest and Red-tailed Hawk Night Flying

See the phantom Red-tail flying through the night skies of Tulsa?

And another. (Images courtesy of KJRH TV Tulsa)
Many emails have come in with questions and comments concerning Thunder's penchant for returning to the nest so frequently and for more information concerning Red-tailed hawks flying around a night.
Here's a sample and Red-tail expert John Blakeman's opinions on the matters at hand.


Catbird a Tulsa Cam watcher tells me that last evening, Thunder went off the nest at around 8pm, the station turned the cam around for a view down the street. As there are cam watchers 24/7 several swear they saw RTs flying around in the dark. Also sometime between 2 and 4 am Thunder inexplicably reappeared on the nest. Do you know anything about RTs flying around at night? I did read something the other day about creatures we thought were completely diurnal will shift depending on food availability. And I have seen them shift for short hops with what seems like reason after dark/ Then Rob Schmunk of Bloomingdalevillage.blogspot.com reminded me that last season he observed the formel on the Queen’s cam leaving at night.
Best, D

Well, here's just another example of where dedicated non-biologist hawkwatchers can so significantly contribute to our understanding of the natural history of this great species.

Do Red-tails fly around at night? Well, of course not. I've had many a trained and acclimated Red-tail on my fist at night (I'm a Red-tail falconer, as many know), and many a time I've tried to discern the hawks' ability to see at night. My best estimation is that they can only see about as well as we can. From my experiences, I've always presumed that when the sun goes down, a Red-tail just better stay put on its evening perch. If it starts flying around at night, who knows what tree branch or powerline pole or wire will it fly into and break a wing bone.

That, at least, is pretty much the conventional wisdom on Red-tail night flying.

But from accounts like the one from Tulsa, and from some personal observations of wild Red-tails I've seen, I now think it's wrong.

First, on several occasions I've seen where Red-tails have gone to roost at dusk on tall, open utility poles. I know that in calm weather, many like to spend the nights on these high, open perches.

But on a number of occasions I've noticed at dawn that the hawk had left the pole and spent the night elsewhere, almost surely in a tree, which it would have had to fly into at night. Unless it could see well enough, it could easily break a wing flying into a tree, crashing into a big branch at 35 mph.

Peregrine biologists here in Ohio discovered that a pair of Toledo falcons commonly flew at night out over Lake Erie and captured migrating birds, often mockingbirds, and brought them back to the nest in the darkness of night.

At dusk, no dickeybird feathers were in the nest. The next morning, new prey or their feathers were in the peregrine nest. The adults were radio tagged, and they could then be followed as they flew out into the pitch black darkness several miles out over Lake Erie during the spring migration.

Just how the peregrines could see the migrating songbirds is unknown, but they did. Almost surely the falcons were using portions of the spectrum higher (ultraviolet) or lower (infrared) than the visible spectrum we mammals use. We now know that Kestrels can see way up into the ultraviolet. The other falcons probably can, too.

Red-tails? We don't know. But yes, the evidence is accumulating that these birds can safely fly around at night. We know that they don't fly in migration at night, but that might be due to settled air column conditions, not a lack of night vision.

Still lots to learn about this common (but so majestic) species.

--John Blakeman

And from Betty Jo of CA,
Its almost 8:PM in Oklahoma and Thunder is back in the nest. Since she fledged at 6:00 am this is 10 full days and she's back in her bunky. What a bird! The wind seems to be trying to make her a bald bird.
Betty Jo
From Sally Seyal of Kentucky

I know you, too have been following Thunder in Tulsa. I was curious what the history of red tail eyasses fledging then returning repeatedly to the nest? Not branching, but fledging then flying back day after day to the nest like thunder is doing. I don't recall Pale Male's kids doing that, nor Jr. and Charlotte's, and this tower is HIGH from what I've been reading.

Thanks! I enjoy your site and the several others I read daily!

Sally Seyal
Prospect, KY
Sally, for the New York City point of view, I know of one season at least in which an eyass or two made it back to the Fifth Avenue nest but it's rare at that site.
To my knowledge no eyasses were able to return to the Trump Nest nor the one at the Cathedral. But not for want of trying. They just couldn't make it and their parents didn't bring food to the nest once everyone was off. They made food drops or tempted them into trees with prey.
On the other hand, the Fordham eyasses which do have a route back to the nest use it routinely. Though I don't think that they have frequented it for as many days as Thunder has.
First she stayed extra long on the nest before fledging so was strong and well grown. It is way up there after all, and now she has a regular schedule she seems to be adhering to. All Red-tails have clearly individual personalities once you watch them closely as all can see who have followed Thunder's babyhood and fledgling.

From B.J.--Please ask Blakeman if it is common for a young fledged RTH to spend as much time returning to the nest (and napping--so cute) as Thunder does?"

And now for the rural hawk perspective from Red-tail expert John Blakeman--

Frankly, I was just talking with another Ohio Red-tail expert, a falconer friend of mine, on this very issue this morning. He's trying to follow some new fledglings at a nest he's watching.

Actually, neither of us have really seen this return to the nest activity in typical rural nests in trees. But we agreed, after pondering the observations of the nest-returning behaviors of the Tulsa brancher, that they probably occur rather frequently. In tree nests, it's just not so obvious. In open, nowhere-else-to-go-nests like the Tulsa TV tower, this behavior is obvious and clearly observed. With tree nests in forest edges, this fly-out and fly-back behavior is obscured by all the vegetation.

But the brancher surely has a behavioral attachment to the nest associated with getting fed. That's where all of its food has appeared. So when it flies out and gets hungry, it will have strong propensity to fly back and see if anything edible has appeared.

That will all come to an end when the parents start dropping food somewhere else, away from the nest. But for a week or so after being able to fly a bit, this get-back-to-the-next behavior is probably very typical.

Does his suggest that I don't really know much about newly-fledged Red-tails? Yes, accurately, it does. At typical rural and wild nests, the fledglings are hard to track. They fly up into some tree foliage and can often only be heard, when crying for food. After being fed, they just sit up there and cannot be seen.

This is just another reason diligent hawk watchers at nest sites such as Tulsa and New York City can make significant contributions to an accurate understanding of Red-tailed Hawk reproduction.

--John Blakeman

Donna Browne

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