Friday, April 03, 2009

Kay Leaves the Nest for Hours Again, Pale Male and Co. Plus What Happens When Eggs Don't Hatch

Screen Capture by Kentucky Sally of the Tulsa Hawk Nest Forum

An update from Sally about Kay of Tulsa's behavior on Thursday--

Drama continues...
Kay left the nest at 7:52 this morning and did not return until 4:56 this afternoon with an incredibly full crop. Jay has sat on the nest all day. She only stayed about an hour, calling while sitting and obviously full, then stood up and left. Jay is still on the nest as of 6:57 p.m.

Can a male keep the eggs warm enough -it is supposed to be 34 tonight-over that long of a time period without the brood patch females have?
If nothing else, this nest is giving us lots of questions to ask and things to learn. I attached a screen capture of Kay's crop. I think she ate a softball!

And the question remains, Sally, what is going on with Kay? Looking back, perhaps Kay's behavior was a little out of the ordinary even before she took to the nest.

Cheryl Cavert, who has taken many grand photographs of these hawks, reported that she observed an episode of copulation in which Kay seemed "uncooperative" initially. I've not seen an episode of non-cooperation on a female Red-tails part. Not that it doesn't happen, I've just not seen it. At the time I thought perhaps their footing or balance was wrong, or that Kay was uncomfortable for some reason. But now with the current aberrant behavior on Kay's part, I begin to wonder if there wasn't something out of the ordinary going on even that far back.

Can males who have no brood patch, keep eggs warm enough during cold weather? They certainly can for short periods of time or we'd never see a hatch. And I have noticed on Pale Male's part, the other males in Manhattan building nests may do it exactly the same way, we just aren't able to see them as well on regular basis, that he takes more care to fluff his belly feathers down over the eggs than Lola does. But then she doesn't really have to because of the brood patch.

As to the long term, the only information I found that compared incubation by males and incubation by females had to do with a question of reverse sexual dimorphism--the females being bigger than the males. Some thought that the females were larger because their increased would do a better job of incubating eggs. This possible reason for reverse sexual dimorphism was discounted as both sized birds were found to do an adequate job of incubation. Though the brood patch wasn't taken into account, one could surmise from the findings that conceivably the female might do a better job, but the male's incubation was good enough for continued viability of the eggs to be maintained in various weathers and temperatures. In other words, perhaps males would take slightly longer to hatch eggs but they'd still get there.

Beyond the fact that the Tulsa nest site has a solid bottom in the tower platform so no wind can puff up from underneath and is well twigged for insulation as well. As far as I can tell it shouldn't be a problem. Far more worrisome are the lapses in egg coverage.

It is drizzling and both birds stand where they are partially protected by the building overhang. Lola eats the pigeon that Pale Male has just delivered with her back turned. While Pale Male studies the nest or scans the territory.

Formels need a good portion of food daily while incubating. Pale Male has just brought Lola an entire pigeon, including the head which at times is left behind or eaten by him in order, we surmise to reduce the weight for the flight up to the nest. This particular pigeon was so meaty that Pale Male had to rest on a terrace mid-way up in order to be able to get it to the nest. Lola ate just about everything edible on the pigeon including the primary feathers of the wings.

Another good question from Sally--


Does Lola take a long break with her meals? And do you know if there is any "usual" frequency of meals for a nesting female-I apologize if this has been answered already. I was just curious if there is a usual length of time she is off the nest. If Pale Male is bringing her food she obviously doesn't have to catch her own, so does she go off and preen and stretch a bit? Kay seems to take long breaks 45-60 minutes usually, and I don't know if that means she's hunting for herself or if she's just chillin' taking a good break. Of course I know the limitations of comparing the two birds but what else can we do?

Thanks again.

Sally as you comparisons are limited, as Red-tailed hawks make many of their own decisions depending on their personal preferences as opposed to built in wiring "normal" normal behavior includes a broad. But we can look at what some of the behavior of the Manhattan females in regards to break length.

Lola rarely if ever takes a break of 45 minutes unless she has been on the nest well over the usual incubation period. Pale Male does all the hunting as far as we can tell during the incubation on that nest.

Early on in incubation Lola doesn't appear to be comfortable about leaving the nest for anything more that 5 to 12 minutes for personal business. And during those 5 or 12 minutes Pale Male is sitting firmly on the eggs. She often eats quickly on the nest, at which time, PM will stand on the nest with her, scanning the territory for something that might be a potential danger to her.

About midway through the incubation period, Lola seems more comfortable about eating at a stash point off nest or taking the food Pale brings to the nest to a spot a few buildings away to eat. She eats in a voracious and business like manner common in hawks. Then does a little quick preening and if she isn't on the nest, returns to it. These breaks last from about 12 to 20 minutes. Pale Male sits on the nest when she leaves it.

A break of 45 minutes would be extremely unusual for her unless it is past the hatch date by a good deal many days. On these breaks, when she is actually starting her retreat from the nest, she eats, bathes, preens, and does some strength flying. By the time she returns, she has to wait many minutes for Pale to evacuate the bowl so she can get in--and immediately replace some of the twigs to their original position which Pale moved to make the nest more comfortable for him or more to his taste at any rate.

My suspicion is, she has to wait so long for him to rise out because Pale has gotten into the bowl and is taking a wee nap.

Isolde of the Cathedral of St. John nest, often retrieves the food from the stash point, whips back into the nest and eats it there. There were times in the 2oo8 season when she had to do her own hunting as Norman was young and not altogether reliable about remembering to hunt for her. A few of those breaks may have been around the 45 minute mark. Though as Isolde sits in a spot where she can scan for prey while sitting, I believe she often has good hunting spots in mind and therefore doesn't have to do much waiting for prey to appear and can hunt and eat rather rapidly. There were occasions when Isolde wasn't fed, made sure Norman was on the nest, left to hunt, eat, then returned and sat on the roof of the building across the street watching the nest with Norman on it.

Often with her previous mate Tristan, this had been the pre-position for a nest switch. Whether she was just taking her ease or waiting in fact for Norman to get the idea that he should leave to the rear while she flew in the front wasn't clear

Charlotte, the female of the Southern Central Park pair, on occasion does her own hunting as a preference because there are episodes in which she looks disgusted by what Pale Male Jr. has brought and wants something else. So she rejects the prey he has brought. "WHAT, pigeon again!"and goes and gets what she wants, perhaps taking about 30 minutes from start to her return to the nest.

5/18/07 The eyasses on the Cathedral Church of St. John the Divine, watch as their mother heads their way with prey.

5/18/07 Isolde tears the prey and feeds them. Carefully making sure that whoever was fed first the last time isn't fed first this time. Or if the largest eyass had been first last time, she will give her a couple bites, then feed the other. If the first attempts to horn in she vocalizes deep and sharply and the larger eyass lays back while the smaller is fed. I know that both Isolde and Charlotte do this sort of portioning out of prey. I expect this is a learned behavior of more experienced parents, though I have no way of knowing for sure.

I also don't know that if there were a shortage of prey how the distribution would differ if any.

5/18/07 Note this is the same date as the above photographs. While other nests have progressed from hatches to eyasses already up off their haunches, the Fifth Avenue pair have been doggedly still sitting on their eggs. Lola's breaks have been becoming more extended daily.

And on this day, Lola has finally left the nest possibly for good. Pale Male has been sitting for hours, and is watching with focus (and concern if one reads hawk facial expressions) for her to return.

5/18/07 Towards dusk he is still there waiting for her to return. I believe this was the last day in which she sat the eggs that season. I was not there at deep dusk to know if Pale Male spent the night on the nest. As far as I can find out there has not been a confirmed sighting of him ever overnighting. Doesn't mean he hasn't, just means I don't know for sure.


From Tulsa Hawkwatcher Bob McCargar

I wrote to Blakeman and asked if the hawks could sense whether the eggs were viable or not, and about the "cold and wet nest and Kay theory. Here's what he said:

With certainty red-tails have no understanding or perception of egg viability or health. If they did, my red-tails back in my breeding trials in the early 70s wouldn't have so diligently sat on the wooden eggs I used to entice sitting before real eggs were laid in later years. Unhatched hawks in eggs do not make any noises that communicate to parents, at least not until the last days before hatching. And the bird will sit for many weeks on dead or wooden eggs. They don't count days of incubation. They merely give up when the day length is no longer expanding, when summer approaches, and nothing has hatched. The wet feathers and nesting material should have prompted the bird to get right down on the eggs and keep them warm. Again, this was very aberrant nesting behavior on the part of the female. I can't explain it. And let's see what happens. If the egg hatch, it will be a remarkable new piece of incubation knowledge regarding the lengthy cooling period of the eggs. We frequently see unprotected open cooling periods of 10 to 20 minutes, but seldom anything at all beyond that. Periods of 20 to 30 minutes are presumed to be the cooling limits to viability. I wouldn't be too concerned if this happened in the first days of incubation. Before the embryo begins to develop significantly it can withstand long periods of coolness. But after a week or so of constant incubation, the egg is committed to reasonable warmth during continuous incubation. Keep me posted on what happens.
John A. Blakeman

It's going to be an anxious couple of weeks for the Tulsa forum members.


From Bob McCargar--
One of our members had a computer failure, and so she's been going to the local library in Bartlesville. She found your friend Marie Winn's Red Tails in Love, and used the computer there to send this note:

Hi, bobd and company: Still no computer at home, but I wanted to post something relevant, even if not on the observation thread. In light of the dramas we are seeing and have seen at the nest, here are a couple of thoughts for your consideration from Marie Winn's Red-tails in Love book. I think you will find truths here that touch your hearts:

"Bird-watching is a sport, a hobby, a skilled occupation. Hawkwatching is an obsession. Like love, it exhilarates. Like love, it brings anxiety. Birdwatchers watch and listen, ever in hope of something exciting just around the corner. Hawkwatchers exalt and despair." (p. 204)

"The red-tail fledglings hung around a few weeks and then they, too, were gone, God knows where. Only unhappy stories have real endings, after all. You never find out how the good stories end." (p. 263)


We've all exulted with Kay, Jay and Thunder over the past year. We've had our despair, as well, with little Spirit. Maybe we will despair again this season. Maybe there will be another unhappy story with a real ending. But then we will still have Kay and Jay, and we will still have one another, hawkwatchers all. We will exult again, sooner or later, and one way or another. And we will continue to hope that Thunder is out there living her own hawk's life--and that, for us, may be the Good Story with the hidden ending.

(An aside here. If you have not read Marie Winn’s glorious book, Red-tails in Love, run do not walk to the book store or the library and get it! You will be so very glad you did. Marie also has a second book, Central Park in the Dark, which continues the saga of the Watchers of Central Park with some cameo appearances of the Red-tails with the inclusion of the night creatures-the owls, the raccoons, the moths.)

From me--
Bob, thank you for keeping me in the loop. John’s great isn't he?

He's right of course the parents don't know if the eggs will or won’t hatch. Every failed season, the last five I believe, Lola sits for an extra month and the weather becomes hotter and hotter up there on the building, she becomes more bedraggled and worn. Poor bird, she gets itchy, she gets giant bags under her eyes, the flies torment her, and when the pigeon spikes from the undercarriage were still poking up through the lining of the nest, her brood patch became completely purple from bruising. But she still did that extra month.

Pale Male faithful and diligent to the end keeps bringing her food and taking his turn at the eggs. They both seem to know "something" isn’t right but not what. They begin remodeling the nest, searching for new materials and poking them in with focus.

Then Lola’s breaks get longer and longer and Pale Male sits and waits longer, looking very concerned, watching for her to return to the nest. Then a day comes when she just can't do it anymore and he will sit all the day long waiting to be relieved. His little face staring out searching for her return. Then if he sees her sitting nearby, he'll fly off the nest. He’ll raid a passerine brood of a chick and fly back and forth in front of the nest, trying to tempt Lola into returning. She may fly to the nest for his offered treat but then she leaves very quickly again. Her hormones are no longer urging her to be there and it has been physically miserable for her for weeks. He then often takes the egg sitting job for himself until he too can't do it anymore.

Then they start their journey from the nest in the reverse order of how they came to it at the beginning of the season. Copulation, courtship dancing in the sky, nest refurbishment, until they pass once again into the trees of Central Park to do the things they usually do come winter but a little earlier as there are no fledglings to train.

Lola was photographed playing with a juvenile not her own, in one of those failed years after she and Pale Male had left their nest. Perhaps she was playing with one of Pale Male's grandchildren..

The hawks do not seem to grieve as we might and do, they are practical and take things as they come. They will start all over again when the cycle of the seasons returns them to January's nest building and it all begins again. So we try to take a cue from them, and every season there are hawkwatchers sitting on The Bench even now-- watching with their fingers crossed...hoping.

Beyond that, as you know these birds are beautiful, they fill us with wonder, and the surprises never stop no matter how many years you watch. Sometimes the surprises are terrible and in other years so full of joy they are nearly miraculous. Marie is right; hawkwatching is an obsession.

How could one not want to see what happens next? We wouldn’t trade a minute of it.

Every year we hope beyond hope that Pale Male and Lola will succeed, and then deep in the season, comes the despair—at least so far. If Pale Male and Lola are ever successful again, there will be true exaltation in New York City and in many other places too, as so many know the Fifth Avenue Hawks.

I have my finger's crossed for Kay and Jay too, though I don't logically know how the eggs could still be alive. But do remember the hawkwatchers adage..Never Underestimate a Red-tail. Besides there is always the next hawk season. When not only do the birds begin anew but the hawkwatchers once again gather together as well, a flock of old friends return to their former places almost as if they have never left. They catch up with each other, and with eyes ready for wonder, wait and anticipate just what this new season may bring.


From John Blakeman—
I wouldn't take any concerns about the pair failing to return to the nest site next year. They've been there now for, what, two yeara? If they didn't come back, it would almost surely mean that both birds would have died. After red-tails nest consecutively at sites like this (and at 927 Fifth Ave in New York), the birds will come back. They aren't coming back because eggs hatched or failed to hatch. It's the nest site itself, one that they've grown accustomed to and feel "at home" in.

Donegal Browne


Sally said...

Thank you for your patience and your responses. Just for clarification, the KJRH tower nest has a metal grate as its floor, it is not "solid" per se. This I am sure is usefull in allowing water to drain out.

Donegal Browne said...


Oops. Thank you for the correction concerning the floor under the Tulsa nest. Could you make a guess as to how large the holes in the grate are?

Sally said...

Donna, I don't know about the grate but I sent you a picture-maybe you can tell what you need to know from it.