How much sex for another egg?

I wonder how many work hours were lost yesterday as we anxiously watched the nest for the appearance of a second egg?

Though the single egg was faithfully attended by a parent hawk most of the time, there were periods yesterday when neither hawk was on the nest, and then observers on the ground reported seeing them copulating. The question then asked was "Does each egg have to be fertilized and then it will be laid?"

At the rate our happy hawks have been observed "doing the deed" the nest would by now be overflowing with eggs!

John Blakeman gives us another chapter of hawk knowledge:

"No, a single copulation event is enough to supply sufficient sperm to impregnate all the eggs, one, two, or three. Many falcons for falconry are captivity bred with artificial insemination, and a single introduction of semen into the falcon's cloaca is usually sufficient.

But let's face it. Red-tails like to have sex. They do it frequently, from late January (or earlier) all the way through the breeding season. Some birds even copulate in June, right in the view of the new eyasses (Have they no shame?)!

That, of course raises the question of the neural responses (well, let's be plain, the eroticism) of the birds. In this venue I won't speculate too deeply (Is that the word?) about this matter. But I don't think it's much like human or mammalian sex. Still, the hawks like to have sex. They like the amorous preliminaries, the stooping flights (which aren't always necessary) and the come-hither bowing of the formel, etc.

As with humans, the sex act is a significant and reinforcing factor of the pair bond. I find it hard to convey the significance of this, how each bird so calmly, even lovingly, in a hawk-like way, so easily tolerates his or her mate. This is not the basic nature of these birds. They are independent, isolated, and otherwise self-sufficient. Except for breeding, they have no need or interest in social interactions with other red-tails. Only in this pair-bond arrangement do these things so wonderfully happen, and at the Franklin Institute we get to see them so intimately. Just great.

It's about 4:00 PM EDT [on Monday March 15]. I've been watching the formel sitting now for some time. I think she's getting ready to lay once again. The time is right, and she's a bit calmer."

--John Blakeman

However, as twilight arrived on another gray, wet, windy day in Philadelphia, there was no second egg. After sitting on the nest for over two hours, the formel stood up and then flew off the nest, and the egg was left alone as darkness fell.

Perhaps today......