Beauty (left) & Archer (right) at the Times Square nest box

It’s an interesting question, one we’ve heard a lot since our Main Camera started catching the two falcons in the nest box at the top of the Times Square building. The answer is, well… read on.

The presence of both falcons in the nest box, apparently bowing to each other looks a lot like courtship activity. Our watchers haven’t observed the two of them mating since moving to the Times Square building though, so it’s hard to say what’s going on. Then there’s this time-lapse sequence from the 22^nd that seems to show Beauty sitting over the scrape in the nest box and acting very much like she’s got a clutch of eggs to incubate. So what does it all mean?

We talked to DEC biologist Barb Loucks, and she tells us that while renesting is possible, it isn’t very likely. Usually a second clutch only gets laid if the first one failed within about ten days of incubation beginning. Assuming that Beauty did lay eggs at the Midtown Plaza Tower, our best estimate is that she began incubating them on or around April 20. The last report of the two falcons at Midtown was on May 19, and by the 23^rd or so they’d moved to the nest box at Times Squre. So it would seem that, if they were brooding eggs on Midtown, they were at it for about a month. Barb told us that if they do lay a second clutch, it’s likely to be smaller than the first. Add the relative youth (and presumed inexperience) of this pair and the absence of witnessed mating to the mix, and it doesn’t look too good for a second nest this year.

At some point it just gets too late in the year for eggs to hatch, eyases to fledge, then gain the flight and hunting skills they’ll need. If a fledgling hasn’t learned to hunt by migration time, their chances of survival become very dim indeed. That’s because the falcon’s prey– other birds– are heading south too, and the Peregrine needs to “follow the food”, as it were. There are other considerations for the urban falcon, like greater availability of prey year-round, but in general terms there’s a good reason that evolution has programmed falcons to hatch their clutches in the spring. Second clutches and late clutches have been observed– there was even a late clutch in New York State this year– but they’re not the norm.

Renesting, of course, assumes that Archer and Beauty had in fact laid eggs on the Midtown Plaza tower. We suspect they did, but we don’t know for sure, so making a definitive statement about Beauty’s odd posture in the box isn’t really possible. Barb and Mike Allen have expressed interest in getting a look at the possible nest site on Midtown later this year, but no firm plans have been made for that. And with the demolition at Midtown scheduled to begin later this summer it may not be possible to view the ledge where the falcons spent so much time before moving to the Times Square nest box.

So what about their other behavior? Barb notes that their courtship may never have actually stopped, or that it might just be starting up again since they’ve found a nesting site. When falcons do lay a second clutch in the wild, it is often at a separate nest site from the first. Maybe all of this is like the late courtship/pair bonding behavior we’ve seen from Mariah and Kaver in past years just prior to Kaver’s migration, but pushed back a few months because Archer and Beauty didn’t have a brood of eyases to raise.

Barb told us that ours isn’t the only unusual find for Peregrines in New York state this year, so maybe there’s something in the air. Besides the late nest, there has also been a successful fostering attempt and some new nest site discoveries. In the meantime, mysteries abound here in Rochester. It’s fun to watch, and we all get to observe something new and learn together! So will Archer and Beauty yet lay eggs in their new-found nest box? Here at the Rochester Falconcam we never say never, and our unofficial motto, Specto Subitus is in full force this year. We’ll just have to wait and see what happens.

This entry was posted on Friday, June 26th, 2009 at 2:54 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.