Friday, April 04, 2008

Pale Male and Lola Fly Together and The KJRH Red-tails Have a Hatch

Pale Male and Lola come off the nest for a three and a half minute flight together over the Model Boat Pond area, Wednesday morning. Lola ate the brunch Pale Male brought for her on the nest and then did some preening on her break over on Stovepipe.

Live action cam plus great highlight footage of the feeding of very small eyasses and the second egg hatching. Both activities we seldom get to see and never from our perches on the ground.
Donegal Browne

URBAN HAWKS: A Visit with the Intrepid 79er's



Wednesday, April 02, 2008

John Blakeman on "Leaving The Eggs Uncovered"

Pale Male's 2007 eggs. Note the height of the nest walls and the small fragment nest lining, both of which would, in normal circumstances, protect the eggs from drafts and sudden cooling during a parental break from the nest.
And as promised, John Blakeman on raptors, and leaving eggs on the nest unattended--

I, too, saw the posting at noting the 11 minute absence of Lola from incubation on the nest. This would seem to be a lengthy period of the bird's absence, during which it might be presumed that the warm eggs would cool and perhaps die.

But those of us who have studied rural Red-tail nests have seen this often. When first noticed, we all are greatly concerned. The sitting bird gets up off the eggs, stands on the edge of the nest, and starts to preen, stretches her legs, and looks around at the landscape's scenery. Frequently, she will also "slice," defecate in the typical Red-tail manner, backing her tail over the edge of the nest and expelling her feces ("slices") away from the nest. In most cases, after just a minute or two of all of this, she then dutifully walks ever so carefully (with folded talons) back over to the eggs and settles in again.

But from time to time, as noted in this case, instead of promptly resuming incubation, the bird inexplicably flies off, leaving the eggs un-warmed. In this case, it was for 11 minutes or so. Here, in our Ohio nests, we've seen incubation lapses of up to 20 minutes.

When seen, this is unnerving, especially in late March or early April, when air temps are still quite cool. One doesn't have to do any thermodynamic calculations to understand that the eggs must actually cool somewhat in these absences. But in virtually every case, the eggs go on to hatch without incident.

We've seen this often enough to believe that periodic, short and mild coolings of the eggs are actually beneficial, for perhaps the following reason. One learns in first-year chemistry that the solubility of gases in liquids in increased as the temperature of the liquid declines. Cold water in a trout stream holds a lot more oxygen than the warm waters of the lower Mississippi. So, could it be that these periodic and lengthy incubation absences are actually methods to allow increased oxygen diffusion through the porous egg shell into the fluids of the egg, thereby providing an episode of more-available oxygen?

That's all prognostication or hypothesis. Someone needs to create an artificial Red-tail egg that detects motion (the egg turning routines) and temperatures, all of which would be broadcast to a nearby antenna and recorded. At the same time, the activities of the sitting adult should be simultaneously recorded on a digital movie camera. Then, we'd get the real story of all of this.

There is still a great deal of scientific ignorance about Red-tailed Hawks. We still can't completely explain everything that this regal species does. Leaving the eggs un-warmed is one of those.

--John Blakeman

Isolde: The Deleted Photo from the Previous Post

Isolde of the Cathedral Nest, April 1, 2008

Tuesday, April 01, 2008

Is Isolde Up There? Plus the Skunk and the Peacock.

All photographs D. Browne
The nest at The Cathedral Church of St. John the Divine

1:44PM So far there's been no sign of either Isolde or her new mate and I've been here for an hour and a half. It's sporadically raining so there is no work being done on the Cathedral and still the nest looks empty. No hawks have perched on Gabriel, nor Tristan's urn, or any of the perches that were used the last two seasons that are visible from the corner of Morningside and 113th St.. Time to check the other views of the nest just in case something is visible that can't be seen from here.

1:56PM Did that large twig that's touching the back of St. Andrew's head just move? Nothing now. Though the twigging on Andrew's left side is interesting.

It's a good example of how the hawks place sticks perpendicularly and horizontally in a kind of raptor basket weaving pattern.

2:04PM Now the view standing east and looking west. Did I just see the top of a head? Nothing visible. Get a grip.

2:34PM What is that?

2:37PM THAT is definitely the top of a hawk's head! Hooray. That is a huge relief. Let's just hope we can all find a way that she won't be disturbed and the Cathedral can continue doing what they need to do but further away.
(There was a photograph of Isolde on the nest here, which was deleted from the page. I'll publish this so you get the news while I work on getting the photo back in. Sheesh.)
And there she is. It's Isolde! (Not.)

2:39:42PM And it looks like she is leaning over to turn an egg or eggs.

2:43:04PM Nothing visible.

2:40:21PM Isolde moves a twig to the right.

There is her back again.

Movement. Perhaps, preening?

2:42:03PM Isolde looks to the west. Is her mate over there?

2:44:48PM Now she looks east.


2:46:07PM Now she stares north.

2:50:47PM Stares left to the west again.

2:51PM Stares fixedly north.

Peering through the twigs or looking down?

Looking down, white spot visible.


Then she disappears from sight and doesn't pop back up again. She's definitely brooding. The small drizzle is becoming a bigger drizzle, time to go.

The daffodils are blooming lushly in Morningside Park. Perhaps the drizzle isn't so bad after all. Besides it's warm today. That's when I hear the Peacock scream. Wow, that was intense. It could have been a badly played brass instrument. The drizzle has stopped. I'll walk round. Perhaps see New Guy somewhere inside the close or see the screaming peacock.

There he is! Looking like he's on his way to a debutante coming out gala. He begins to spread his tail and arc it into position.

A big gust of wind comes through and he has to do a little side trot to regain his balance but he's doing it by refolding and lowering his tail. It does not pay to look uncool during mating season.

And it really is a dynamite tail. Though for most of the year it would seem to be rather a challenge to live with.

But in Spring, it really can't be beat. He spreads his tail, arcs it and slowly turns shivering the tail feathers while wiggling his small wings, and turns at the same time. When you think about it that takes an amazing amount of physical coordination.

And there it is, the full spectacular display. He screams repeatedly, does several more displays and there is another peacock scream in return.

He thinks about that. Screams again.

And then hustles into the bushes. Interestingly suddenly there is the odor of skunk. I don't mean as if he's just been sprayed but there is a medium strength skunk odor. This is very strange. I'm in Manhattan. I didn't know we had skunks in Manhattan. I've spent a good bit of time in the country and this odor is without a doubt skunk.
Unless of course peacocks spell like skunk in the springtime. Somehow I doubt it. St. John's seems to be harboring one of those sharp toothed black furred guys with white stripes.
Now that's a photograph I want.
Donegal Browne

Western Tanager, Accipitor, and Red-tail Update

Photograph by Eleanor Tauber

Yes, the Western Tanager is still hanging out in Central Park and Central Park photographer Eleanor Tauber managed to track him down.

And he was even polite enough to look directly into the camera. One does wonder though how he managed to get here in the first place. Did a storm blow him off course? Did he get an accidental "ride" to the East Coast somehow? Or is he just the adventurous sort?

Eleanor also managed to snap this Accipitor. Anybody care to down on whether it's a Sharpie or a Cooper's?

Lola on the Fifth Avenue Nest by D.B.

The Divines At St. John's: Words in from Glenn Phillips of NYC Audubon-- the folks at St. John the Divine are concerned about disturbing the Red-tail nest and have asked for suggestions as how to be less disruptive short of stopping work all together. I've come up with some, and will head up there tomorrow in hopes of coming up with a few more.

If you have any suggestions send me an email!

George and Martha at the Highbridge Nest--Rob Schmunk has some very nice shots of the nest in a terrific tree plus both parents, check it out.

Charlotte and Junior at 888 7th Ave.--It rained rather heavily today so Brett Odom was unable to ascertain whether Charlotte was in the "box" sitting the nest or not through the wet window. He'll be checking again tomorrow.

And now to our old friends Pale Male and Lola--Lincoln Karim of www. posted that Lola had left the Fifth Ave nest unattended for 11 minutes. I've received several emails asking if that might not be detrimental to the eggs as Saturday was a touch chilly. The short answer, it's probably no problem at all. According to the literature, the major causes of egg death are due to cold drenching rain and if the female must leave the nest frequently and vacant for longer periods as she must hunt for herself in order for she and her mate to get enough to eat.

As for the longer answer, I've asked John Blakeman to send in the expert opinion.

Donegal Browne