Friday, January 29, 2010

Red-tailed Hawk Update--Kay and Jay in Tulsa, Isolde and Norman Uptown NYC, John Blakeman, Two Peregrines vs RTH, Plus Samantha Raven and Buddy

Photo by Francois Portmann
Here is Samantha Raven's buddy, the young Cooper's Hawk.
Here we have a great view of one of the ways to tell a Coop from a Sharp-shinned hawk. See the bottom of Buddy's tail? It's rounded. A Sharpie's tail would have a blunt end.

Photo by Francois Portmann
From Francois Portmann in regards to my questions as to possibly why these two, a Raven and a Cooper's Hawk, might be keeping company. (By the way, the first time someone wrote to me about Samantha Raven she was being visited by a trio of Crows. Usually a threesome of Crows means they are a foraging party.)

Well not sure about that duo.
People feed Samantha and that could be a reason for the Cooper to be there, maybe he gets scraps!!
Red-tail hawks catch pigeons there regularly, that’s more left overs too.
The Cooper is active and alert, keeps hunting around the place but I’ve not seen him catch anything yet
Looks well fed though! (pics last nite and today in the snowstorm)
["Today" would have been Thursday, 01/28/10]
See you,

Well fed? I'll say. Just look at that crop bulge.

I take it you have never been around when both the birds are there and Samantha's meat is brought to her? Would you care to experiment and find out what happens?

As food is already being brought in, it wouldn't be teaching either of them anything they didn't already know. I think I'd be very tempted to put it to a one time test to see what happened.
Photo by Cheryl Cavert
1/14/10 Jay does some work on the nest.
From Tulsa Hawkwatcher and photographer Cheryl Cavert, some photo history of Kay and Jay's alternative nest site--
Hi Donegal,
A few photos from January 14th and 18th, 2010 that show Jay at the alternative nesting site and a few views of the nesting material. Jay is perched a level below the nest - however I still did not notice the nesting material gathering for a few more days!

Photo by Cheryl Cavert

Photo by Cheryl Cavert

Photo by Cheryl Cavert

Photo by Cheryl Cavert
1/26/10 Visit by both Kay and Jay
Also from Cheryl Cavert some commentary on the photographs--
The first photo from January 5, 2009 does not appear to show any nesting material on any of the platform levels.

Photo by Cheryl Cavert
On May 1, 2009 sticks are visible. This was a few weeks after their nesting failure on the KJRH tower; however, I do not have any photos taken in between those dates so I cannot confirm when they began depositing a few sticks there

Photo by Cheryl Cavert
The third photo is from October 31, 2009 of Kay at the alternative tower - we still did not notice the sticks gathering on the platform!
(More photos from Cheryl of Kay and Jay coming soon.)
Upon request, here is what John Blakeman has to say about the Tulsa nest situation. Plus more on hawks and pigmentation.


I can’t tell much about the status of the Tulsa red-tail nests. It’s not that the photos are inadequate; rather it’s because it’s just too early in the reproductive season for anything to be firmly set.

Right now, the breeding pairs are just going through motions, with nothing firmly set yet. Nest construction right now is generally pretty cursory and incomplete. As you mentioned I believe, red-tails commonly will start building alternative nests in January and February, but then when things get serious in March (at least in the northern tier of states, earlier in the South), the pair often goes right back to an older, well-established nest and finishes the nesting season there.

Or, they just up and abandon the old nest and go to a new one, even if the old one is in good shape. Now Pale Male has not done this, but nest site fidelity with the other Manhattan red-tails has not been as consistent. I see this with my rural red-tails, who rather frequently build and use a new nest less than a half-mile from the first one.

Sometimes this is prompted by a great horned owl, which drops in and expropriates an existing red-tail nest very early in the season, often in December. But more often, the hawks just elect to build a new nest nearby and use it. Why this annual nest site vagrancy? I don’t know, other than, perhaps, for the strong pair-bonding that results from nest building. The birds just love to carry sticks and lining around and build a nest. It must be a very gratifying and psychologically rewarding thing for them to do. They expend a lot of energy carrying all those sticks around and tucking them in to make the foundation of a new nest. Then, they have to bring in many flights of leaves, lose bark, and dead grass clumps to form the insulating lining of the nest.

The pair spends a lot of time and energy in doing all of this, often with no useful physical result, when they go back and use the older nest. They must really like all of this nest construction.

Too early to tell about the posted nests, however.

In an earlier posting, my explanation of the source the skin color in red-tails was incomplete. I mentioned that the intense yellow color of the skin on the legs of haggards was derived from the carotenoids of vegetation found in the gastrointestinal tracts of the prey they capture and eat.

But I forgot to mention that they do not gain any coloration from the fur or feathers of their prey. A hawk might capture a very colorful bird, a blue jay for example. But none of the colors in the feathers of these birds could ever end up giving color to the hawk’s skin or feathers.

That’s because in birds, feather colors come from only two sources. In most, the colors are forms of melanin, which when eaten by a hawk gets completely digested, so it can’t end up yielding any color in the hawk.

The second source of feather color is without any pigmentation at all. It’s by refraction, where microscopic structures of the feather bend or refract the reflected light, allowing only certain frequencies to be reflected. This is the case with blue jay feathers, which have absolutely no blue pigments at all. It’s all, as it were, light and mirrors, or at least light and light refraction into blue hues.

So, no, hawks don’t derive any skin or feather color from the skin or feathers of the prey they eat.

–John Blakeman

That's a great point about the hawks and nest building. It being that time of year, the hawks have a great urge to build. Satisfying that urge would feel good. Just in the way, when we humans have a great urge to do something and we do it, often there is a feeling of great satisfaction.
Or in the case of the descending urges from hormones when leaving a nest, particularly a failed one, pairs may start building a second nest or in Pale Male and Lola's case twigging activity before leaving the nest ( a month later than there should have been the cues of a hatch to trigger the next stage of hormonal cascade) they go through an agitated period of bringing in new material and nest rearrangement.
It's official...
...we are clearly the preferred roosting spot for very cold nights!
After a long hiatus, our feathered friend is back, nestled on the second step of the fire escape. I assume the mate is a few apartments down, though I didn't see him from the sidewalk and I'm not sticking my head outside the window to check.

It's supposed to stay cold through the weekend, so here's hoping they stick around for a few days.
I had both Peregrines attacking an adult Red-tailed Hawk today at noon over the north end of Morningside Park. The hawk eventually landed at the second to the top air conditioner of a tall brick building along Morningside Ave. They like those spots along Morningside because they are out of the harsh wind. Plus they provide a blind from those nasty peregrines!

James is being facetious of course; he is speaking from the Red-tail's point of view. He doesn't really think that Peregrines are nasty as he's been watching the pair on Riverside Church for years. His "watching" has included such activities as running into traffic to help one of their fledglings who had plopped down into the street.
Donegal Browne

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