Tuesday, May 13, 2008

The Frounce Discussion Continues and a Red-tail Update on the Fordham Nest

One of Tristan and Isolde's very healthy juveniles from the Cathedral Nest, 2007

Premier urban raptor rehabber, Bobby Horvath, joins the frounce discussion and shares his experiences treating urban wildlife--

As far as the frounce discussion, I see it quite often in Peregrines, Kestrels, and Red-tails here. Most of the time it occurs in juvenile birds but it can hit adults as well. Just last year I had two peregrines die of it from the city, one banded adult and the other a juvenile. Over the winter we saw at least 6 juvenile Red-tails with frounce as well. That doesn't take into account the birds that die from it and are never found.

Young raptors are very susceptible and most adults may have some resistance to it unless they are somewhat compromised health wise. The one adult I had last year had just fledged her babies so she was thin and probably exhausted. And that’s why the disease was able to impact her so seriously. I suspect that raptors outside cities don’t have anything near the problems that we experience here. Frounce is much more prevalent in New York City than most people know.

Things are about to become very busy. I’ve just started getting in some young critters here and the full swing of baby season is just around the corner.


Which only goes to show that the care we take in the observations of urban raptors is important and we should cherish every one one of them as special no matter the number, as it isn't easy making it in the big city.

The Fordham Hawks--Hawkeye on the left and Rose on the right.

There had been some concern that with the poor weather and the fact that one eyass had been lost already at the Fordham nest, possibly to illness, that another could be lost. Here is Fordham observer Chris Lyons' update of today--

I finally got back up on the roof of Dealy Hall with my scope, and at first all I could see was two young hawks, sometimes moving around, mainly resting. Then Rose showed up and and there was a little feeding, and a lot of preening. I could rarely see more than one chick at a time, but I knew there were two, and was starting to conclude that with the bad weather we've had since three were last seen and a possible contagion amongst the clutch that might have taken the first eyass, that perhaps there really were only two now now.

Then I realized I could see three little beaks in there at once--four, counting Rose's much larger beak. I never got a very clear look at all three at the same time (Rose kept getting in the way), but I am positive there were still three today.

So what Rich photographed was probably a repeat of what happened the first year they nested on Collins. Rose laid four eggs, but wasn't able to rear four young to maturity. I'd hazard a guess that what's happening here is that she's so well nourished that her body is stimulated to produce four eggs--probably the outside limit of Red-tail fertility, or very near it. But perhaps she can't incubate all four of them sufficiently, and one chick doesn't develop properly, and doesn't survive long after hatching. This may have happened last year as well, for all we know.
It doesn't seem at all likely that poison was the culprit, or inclement weather, or disease. Perhaps the dead eyass never even had a chance to be fed. Beyond the fact that four eyasses is quite a lot to handle, even for two healthy experienced Red-tail adults in possession of a prime hunting territory.

So they are literally three for three now--this is the third year in a row they've had three healthy hatchlings. With a bit of luck, all three will fledge in a few weeks.


It's very nice to get the good news of a reassuring update from the Fordham nest. If you haven't seen the news today about the Cathedral Nest Adult vs the Construction Worker, scroll down to the first blog of today.
Donna Browne

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