Saturday, May 26, 2007

Blakeman writes and my further efforts stymied

A few days ago John Blakeman sent me a letter speculating about PM and Lola's third nest failure.

I forwarded the letter to my NYC Audubon liaison, and put in a big bid for continuing to try to persuade the DEC to retrieve the eggs. The response at NYC Audubon was polite, sympathetic but negative. Basically the informal answer I received [not final NYCA policy, however] suggested that they felt there was nothing further to be gained by testing the eggs. The main reason [which is not entirely unreasonable, though a bit too timid for my liking] is that the Board at 927 Fifth Avenue would never, never allow the "cradle" to be taken down, or even modified. Well, it brings back a taunt people used to say to scaredy-cats when I was a kid: "Can't never tried."

I've reached the end of my road here, at least for this year. You may wish to pursue other roads.

Here's John's letter, received 5/23/07


I've just had access to a high speed Internet connection and went back to peruse some of Lincoln Karim's pre-cradle photos of the 927 nest. I was astonished.

The photos from both 2003 and 2004 show the outer rim portion to be very tall, much more so than in the post-cradle years.

Secondly, I noticed the original position of the pigeon prong tips, which were attached right to surface of the cornice's upper surface, upon which the nest itself sat. There is no way possible that these short pieces of metal could have extended far enough up into the egg-baring bowl of the then-tall nest.

But when I look at the nest in the last two seasons, the top of the nest appears to be about where it was previously, but it is much shallower because of elevated cradle. And now, the spikes extend up from the floor of the cradle, not from the lower stone cornice.

When I compare the location of the spikes pre-cradle to post-cradle, it sure looks to me that they now extend up into the deep bowl of the nest.

I'm ever more convinced that the spikes are the root of the recent reproductive problems.

Now, we need some photos from off the roof edge, to see what's really down there. I'd like some photos as soon as possible, but we should all be aware that until eggs hatch, red-tails often pile plucked body feathers and grassy nest lining material around the eggs, so right now the spikes might be obscured by loose lining materials temporarily placed there by the birds. The actual bottom of the nest, upon which the eggs sit, may not be presently visible from above.

Consequently, it would be really good to also get photos of the nest from the roof much later in August or September, after incubation has long stopped and summer rains have depressed the loose lining to solid base levels. If spikes can be seen in August or September, they are the problem. (By default, they are also the problem if an egg blastodisk can be stained after retrieving the eggs, or if microscopic studies show inner egg cells to be diploid, fertilized.)

If it's the spikes, a heavy weight on a line thoroughly secured to the roof and guided by an attached pole ought to allow the crushing of the spikes in the center of the nest in the autumn right from the roof. I don't think we need to send a steeplejack over the edge. If the eggs could have been retrieved last year from a suspended pole, some similar device could be devised to bend over the spikes in the center of the nest. That minor accommodation, I believe, will make the difference.

This will violate no provision of the Migratory Bird Treaty Act, which normally protects the nests of such birds. The nest itself would not be removed or displaced, remaining entirely intact and in place. Only the metal wires sticking up through it will be bent over. The birds themselves could care less about such a "disturbance" in October or November.

--John Blakeman

Friday, May 25, 2007

It's OK to post pix of the Astoria Nest! And where to sit for optimal viewing

photo by Jules Corkery -- the Astoria Park Mom and 2 chicks.

Bruce Yolton has more info about regulations for photographing city bridges -- see his letter below. Meanwhile, I'm restoring Jules Corkery's photo to its place in yesterday's post , and also above-- seems it's perfectly legal! And you can find new photos of the Astoria nest on Bruces Blog. Here's a link to click on:

Bruce writes:
I've learned a bit more about photographing bridges in NYC. Under current regulations on MTA Bridge property, photography is prohibited. I was very near the nest, so I may have been on MTA property when I was threatened with a summons.
However, it seems that photographing the bridge from public property is perfectly legal, so taking pictures taken from within Astoria Park would be perfectly fine. The ALCU has a suit against the city pending about ambiguous policies toward photographers. It seems that the department has ambiguous policies which led to the accidental harassment of photographers.
I think my situation was similar to the problems birders have been having with scopes on tripods in city parks. Well meaning Police Officers are stepping over the line, due to ambiguous policies and poor training.
So, I'm going to post my Astoria photographs on my blog, [ see link above] and you should feel free to put back Jule's Corkery's photograph.

PS Jules Corkery writes:
The best and safest place for binocular viewing of the nest is the benches at the south entrance of the tennis courts. At first, birders might think the view is too far away but because of the height of the nest, the perspective at the benches offers a clear view of nest activity and is a comfortable shaded place for birders to sit. As the evening sun sets, the light is perfect for viewing the little ones having their evening meal. Also, I'm sure the birds and police appreciate the distance!
Great information from Blakeman too. I feel that we're learning so much from our urban birds and I am excited to get feedback about observations!

Yesterday's warbler and a pair of Scarlet Tanagers

David Speiser continues his chronicle of the spring migration. Wonder how he gets them to pose on the same branch? Soon I'll reveal one of his secrets:

Chestnut-sided Warbler

Scarlet Tanager - male
Scarlet Tanager- female

Photos by David Speiser

Thursday, May 24, 2007

More Blakeman on redtails and pigeons and a warning for photographers

Rock Pigeon [its official common name] and dandelions 4/28/07
Photo courtesy of

Sent John Blakeman a note about my recent post reporting on the Astoria Park nest.

From: Marie Winn
To: Blakeman
Sent: Thu, 24 May 2007 10:42 am
Subject: hunting piegeons

John, just wanted to make sure you note the hunting method described in the last paragraph of my post today. Marie

He replied:

I sure did!
I hope that I'm not overstating this, but let me assure you once again that before Pale Male there are virtually no records of red-tails consistently taking pigeons. Ornithologists and raptor biologists haven't seen or reported this, and falconers, many of whom tried to persuade their hungry, motivated, and powerful red-tails to pursue wild pigeons, just have no experience with any of this. The standard dictum of both raptor biologists and falconers is that red-tails don't consistently take healthy, free-flying pigeons. They can't. The hawks are too big and slow, the pigeons too fast and agile.
Obviously, NYC red-tails---and probably others in other urban areas loaded with pigeons---have recently learned how to effectively and consistently take these non-native columbids.
I know for certain that my wild rural red-tails aren't wasting a minute trying to take the pigeons residing around rural barns and grain elevators. We've got pigeons out here, too, lots of them, but they can easily out-fly and avoid any pursuing red-tail.
The difference, I believe, is not the hawks nor the pigeons themselves. It's the city environment, which has a multitude of building and bridge corners and edges, around which a knowledgeable and practiced red-tail can swoop against the local pigeon population in flighted stealth. No one can deny that in open air a pigeon can easily out-fly a red-tail. In a straight tail-chase pursuit, the pigeon simply accelerates away from the big hawk, who in level flight can hit at best 40 mph. The pigeon can power itself to 45 mph or more.
Like so much other urban red-tail biology, we are watching here the selection and adaptation of brand new hunting behaviors never seen in the species. It's really a shame that no one is seriously studying any of this. If this were a rare hawk, as with the peregrines a decade ago, grad students would be working on any number of master's theses offered by this remarkable new urban raptor population.
But these are only red-tails, the most common large hawk in North America. The authorities know everything worth knowing about this frequently-encountered hawk. There just couldn't be anything more to learn about the species, especially from putatively aberrant members of a new, atypical urban population.
On behalf of future biologists, who will someday uncomfortably refer back to your many postings on these phenomena to rediscover the new biology we are witnessing today, I thank you greatly. There are few higher pleasures for field biologists than to observe, describe, and then explain new wild animal behaviors. Frequent pigeon-killing by NYC red-tails is just such a phenomenon.
--John A. Blakeman

PS A warning for photographers

In case you are now inspired to head for Astoria Park and photograph the nest on the Queensborough Bridge, Bruce Yolton sends a warning, (based on recent experience):

It is illegal to photograph any NYC bridge without a permit!

[I guess I'd better remove Jules Corkery's nice photo from the blog, just so she doesn't get in trouble.}


Another urban redtail nest -- this one in a thrilling location

Astoria Park nest with 2 chicks 5/20/07
photo by Jules Corkery

Jules Corkery, a birdwatcher I met in Central Park a year or two ago, has just sent me this exciting photo and a report about another urban redtail nest I haven't reported on before. It is in Astoria Park in the borough of Queens. The nest is located on the southeast corner of the Queens side of the Triborough Bridge, above the tennis courts. The nest is secured on the top horizontal pipe and its support arms. The pipes are tubes that run along the base of the bridge and probably hold wiring, etc. [Location description by Jules Corkery]

Jules writes:
Since I've been watching the Astoria nest fairly closely, I've been putting the hatching dates around 5/4/07 - major change in behavior at that time. They're growing so fast!

Last night, both adults were hunting pigeons by perching on the flood lights high above the athletic field and jumping off to grab pigeons as they came flying under the bridge.

Wednesday, May 23, 2007

Divine Chicks-latest rumor says there Are THREE

Two chicks at the Cathedral of St. John the Divine --north facade- 5/20/07
photo courtesy of

Tuesday, May 22, 2007

Manhattanhenge coming up

Here we go again -- our favorite meteorological phenomenon is on its way. Charlie Ridgway, one of Central Park's faithful amateur astronomers, sent me the article as a reminder.


by Neil deGrasse Tyson, © 2001

Manhattan-henge: Sunset down 34th Street
Sunset looking down 34th Street. One of two days when the sunset is exactly aligned with the grid of streets in Manhattan.
Photo © Neil deGrasse Tyson, 2001.

What will future civilizations think of Manhattan Island when they dig it up and find a carefully laid out network of streets and avenues? Surely the grid would be presumed to have astronomical significance, just as we have found for the prehistoric circle of large vertical rocks known as Stonehenge, in the Salisbury Plain of England. For Stonehenge, the special day is the summer solstice, when the Sun rises in perfect alignment with several of the stones, signaling the change of season.

For Manhattan (a place where evening matters more than morning), there are two special days—May 28 and July 11—when the Sun sets in exact alignment with the Manhattan grid, fully illuminating every single cross-street for the last fifteen minutes of daylight.

Had Manhattan's grid been perfectly aligned with the geographic north-south line, then our special day would be the Spring equinox, and if we so designated, the Autumn equinox—the only two days on the calendar when the Sun rises due East and sets due West. But Manhattan is rotated 30 degrees east from geographic north, shifting the days of alignment elsewhere into the calendar.

Upon studying American culture, and what is important to it, future anthropologists might credit the Manhattan alignments to cosmic signs of Memorial Day and, of course, the All-Star break. War and Baseball.

Because Manhattan is so small (13 mile long) compared with Earth's distance to the Sun (about 93 million miles), the Sun's rays are essentially parallel by the time they reach Manhattan, allowing the Sun to be seen on all cross streets simultaneously, provided you have a clear view to New Jersey. Some major streets cross the entire island from river to river without obstruction, including 14th, 34th, and 42nd Streets. While the May 28 and July 11 sunsets qualify as the exact days for this auspicious moment, a few days either side of these dates also work.

Sunset on Manhattan-henge occurs at a cross-street on and around these dates:

  • May 28 at 8:10 PM
  • July 11 at 8:27 PM

Sunrise on Manhattan-henge occurs at a cross-street on and around these dates:

  • December 10 at 7:11 AM
  • January 2 at 7:22 AM

Monday, May 21, 2007

Double Clutching

Recently there's been a certain amount of talk about the possibility of "re-nesting" or double-clutching at the Fifth Avenue nest. In explaining why the decision had been made NOT to retrieve the eggs this year, the DEC's Barbara Loucks wrote that she thought Pale Male and Lola might be re-nesting. Similarly, a few days ago Sally Seyal of KY wrote to inquire if there might be a possibility that the hawks might still double-clutch this year. Now Judy Glattstein of N.J. has sent in the following story from the BBC News that clarifies the issue. The reality: hawks will, on occasion, lay a new clutch of eggs, but that happens only if the first eggs are destroyed or damaged somehow, as in the case of the Scottish Ospreys.

Pale Male & Lola are sitting on intact eggs. They will continue to sit until some instinct finally kicks in or some external signal is received that causes them to finally abandon the eggs. In years past that has happened a month and a half or two months after hatching should have occured. By that time it will be far too late to retrieve the eggs and try to find out if they had been fertilized. If they had proved to be unfertilized, we would have stopped worrying about whether the cause of failure might be something about the "cradle" constructed on the ledge according to a plan approved by Barbara Loucks in 2004.

Now, I'm afraid, we still have cause to worry.

I hope you enjoy reading about the Scottish ospreys EJ and Henry, below, and I hope you clearly understand that there is NO POSSIBILITY that a similar outcome might be possible at the Fifth Avenue nest, DEC experts to the contrary notwithstanding.

From BBC News
Osprey - general
The osprey developments are subject to close scrutiny
A female osprey has become the first in Scotland in a quarter of a century to lay a second clutch of three eggs.

EJ had mated with a rogue male called VS rather than her usual partner Henry at RSPB Scotland's Loch Garten Centre on Speyside.

Henry smashed his rival's clutch but has now fathered a fresh clutch with EJ, staff said.

Site manager Richard Thaxton said the female laid her third some time last Wednesday or Thursday.

The twists during this year's breeding season at the Highland reserve have drawn dozens of visitors but Mr Thaxton said it was too early to say how numbers compare to last year.

He said: "For an osprey to re-lay a clutch of three eggs is very, very rare.

Like all birds of prey, osprey start incubating from egg one and the eggs hatch in sequence
Richard Thaxton,
Site manager

"As far as we know the last time this happened was 25 years ago."

The first egg is expected to hatch on 15 June with the other two on 18 and 21 June.

Provided there is plenty of food, all three chicks have a good chance of surviving, said Mr Thaxton.

'Some competition'

He said: "Like all birds of prey, osprey start incubating from egg one and the eggs hatch in sequence.

"The first chick will be bigger and stronger than the second and third and there will always be some competition in the nest."

Osprey from West Africa have been flying to Loch Garten for 50 years.

This year, the saga of jealousy and violence began when EJ returned before Henry and mated with VS.

When Henry arrived he knew the eggs in the nest were not his and got rid of them by knocking them out of the nest.