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.