Saturday, March 22, 2008

Q & A about the Fifth Avenue nest

View of nest from above--photo courtesy of Glenn Phillips
photo by Jeff Kollbrunner

Below, four e-mailed communications. The first from regular correspondent Mai Stewart, inquiring about eggs in the nest and the latest retrieval. The second is my reply, which I first sent to John Blakeman, to check for accuracy. The third is Blakeman's reply. The fourth is a note of confirmation and clarification from Glenn Phillips, executive director of the NYC Audubon. All together, these notes do clarify the present situation a little, I believe.

Mai writes:

Hi Marie, Do we have any idea as to whether Lola has laid a(ny) egg(s) yet -- and if not, when they would be expected?

Also, any further reports on the eggs taken from the nest recently? You reported that poison wasn't a factor in their failure -- is there any further info re what happened last year? We all assume that it was the nest structure -- is there confirmation from the expert, or any other info? Thanks, Mai

2. Here's what I answered:

Hi Mai,

I'm pretty sure there are newly-laid eggs in there. They are usually laid about a week after Lola begins to spend the night in the nest. By the middle of April, at the latest, we should know if the eggs have hatched or if there will be no hatch

As for the report: you write "You reported that poison...etc." But that wasn't my report. I had just posted the NYCAudubon press release.

As I see it, the main issue has been whether the nest failure was caused by a flaw of some sort in the new cradle (or the way it was set on the ledge ) or whether it was a function of Pale Male's age.

There is a test that can be done with retrieved eggs which can tell, by microscopic examination, whether the eggs were actually fertilized. Had that special test been performed on retrieved eggs during the last three years, that would have settled the question of whether PM's age has anything to do with the nest failure.

But alas, that test was not done. Now, if the nest succeeds, of course we'll know that the spikes were the problem. Our gratitude to the NYC Audubon for fixing that problem will know no bounds. [We will remain grateful to the NYC Audubon, I hasten to stay, no matter what. They did make a concerted effort to deal with a likely problem]

But if the nest fails again this year we won't know much of anything. We WILL know that the spikes probably weren't the problem. But other problems might remain: maybe the stainless steel of the cradle is at fault. Maybe the space under the cradle causes some unexpected cooling problems. OR maybe it's the geriatric factor after all. Pale Male is 17 years old, a venerable age for a red-tailed hawk, [though to be sure he was only 13 when the first post-crisis failure occurred.]

All we can do is keep our fingers crossed now. And if there's a failure, we must really make sure that the eggs are retrieved and analyzed quickly, not for rat poison traces, (that's never been an issue!) but for fertilization.

3. Here's John Blakeman's response, upon reading my letter:

Marie, Everything you wrote is accurate, except for the egg viability tests.

Yes, those should have been done, checking for egg cell diploidy (full, adult set of chromosomes), or, DNA sampling and analysis, or staining of the blastodisc, an embryonic structure found only in fertile eggs, or lastly, a general gross examination of egg contents to see any bones, flesh, or feathers from a developing eyass.

Ideally, these tests should be performed in June, shortly after the eggs are abandoned and before the eggs have a chance to degrade or rot. As it happened at the Fifth Ave. nest, perhaps unavoidably, both egg retrievals were done months after June, when the eggs could have rotted or degraded, negating any of the viability tests.

I've heard nothing back on the results of the analysis of the recently retrieved eggs. I don't know which tests were done, or what was actually looked for. I would like to learn of the disposition of the eggs. One certainly should have gone to the AMNH as both a historical and a scientific artifact.

We still have no DNA samples from either the parents or the eggs, unfortunately. But that's the sampling problem, a social and legal problem with egg removal, trapping and banding of eyasses and adults, or with blood sample extraction. None of that is going to happen in NYC, and I'm not going to even suggest any of it in the future. The scientific methods we can use to accurately characterize and understand wild populations of Red-tails are not available in New York City, for a long list of unconquerable reasons. Raptor science in NYC happens only behind optical instruments (and not so well at that, either).

4. In response to reading a copy of the above correspondence I sent him before posting, Glenn Phillips of the NYC Audubon sent a clarification:

Last year an unsuccessful attempt was made by DEC to retrieve the eggs early enough to tell if they had been fertilized, but because of Lola’s presence on the nest, that attempt was abandoned. (It’s not that anyone was unwilling to test the eggs, but that they were unable to.)

Because the eggs were so long exposed to the elements, there was no material to test anything other than the pesticide/toxin load, which was negligible, as reported in our press release. There wasn’t much more detail to release.

Whatever happens with the nest this year, we will never really know for certain what caused the problems.

PS Glenn has sent me more detailed information about the work that preceded the repairs at the Fifth Ave. nest last December, specifically, the experts' report and their recommendations for action. I'll post some details of this soon.