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