Who can say? If Mariah were sticking to her “traditional” egg-laying schedule, we would have expected to see another one sometime in the afternoon. She is still looking fluffed up and even a little gravid, so it’s possible that she has another egg on the way. Since she’s clearly not keeping to her old pace, we’ll just have to wait and see.

I’ve consulted with some falcon experts and learned a couple of things. The first is that long egg-laying times are not quite as rare as the literature might seem to indicate. It happened at a couple of nests in Toronto, Canada, for example. In those cases, territorial disputes appear to have been the cause, but age, weather and external stresses can all cause egg laying to be delayed. The consensus seems to be that as female Peregrines get older the normal gap of 48 to 72 hours between eggs can stretch, sometimes quite a bit.

It is possible that Mariah laid an egg between the second and third ones that we see in the nest box. We don’t know of any alternate nest sites in the area though. Also, since laying the third egg (and even before) she has been exhibiting typical brooding behavior at the Kodak nest site. She’s also been here almost constantly, so if she did lay an egg elsewhere, it has almost certainly been abandoned.

In fact, Mariah and Kaver have both been spending a lot of time incubating the three eggs in the nest. The picture at the left, from earlier today, shows Kaver arriving at the nest to take over brooding from Mariah. In true falcon style though, Mariah has been doing most of the work, with Kaver taking over only for a couple of hours at a time. When he’s not taking his turn incubating the eggs, he stays near the nest. Usually he’s perched just outside the nest box.

This is a typical pose for Kaver when he’s brooding the eggs. Notice how he’s leaning a bit forward, with his tail up in the air? He sits that way so that he can get the brood patches on his breast in contact with the eggs. It’s the extra heat from the brood patches that causes the eggs to develop. If he just pressed his abdomen against the eggs he wouldn’t transfer enough heat for incubation to continue. So his posture is a clue to what’s going on in the nest.

So, keep your eyes on the Rochester Falconcam! Maybe Mariah’s on track to lay another egg, or maybe we’ll just have three this year. We’ll just have to keep watching and waiting for now.

-Jess

This entry was posted on Wednesday, April 4th, 2007 at 8:40 PM and is filed under Journal. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.