Thursday, February 28, 2008

Riverside pair: she's older

photo courtesy of [click on image to enlarge]

In his comments below about the Riverside Park redtail pair, John Blakeman describes a situation similar to the one Central Park birdwatchers witnessed when Pale Male first arrived in the park. He was a browntail that first year we saw him [1991]. His eyes were yellow. And he hooked up with an "older woman" hawk, one with dark eyes and a red tail. Subsequently we called her First Love. [My 1999 book tells that story in detail.] The sentence I have enlarged [in paragraph 3 below] applies to Pale Male. He was one of those rare hawks of his species to mate before his tail turned red. A remarkable bird from the start!

From the photos today on, showing the two Riverside Park Red-tails, it appears that the golden-eyed, first-year adult, is the "tiercel," the male -- the term is mainly used in falconry. The dark-eyed bird is the female, and in one photo she's shown with some new nest lining material.

How can I, as the biologists say, "sex" the birds, determine their sex? The toes of the golden-eyed bird are slightly narrower than those of the other bird. The same is true of the tarsus, the scaled, ankle part of the leg just above the feet. I've handled several hundred Red-tails, and can visually detect the very slight but visible widths. When I trap a wild Red-tail, the first thing I look at is the size of the feet, the length and width of the toes, along with the relative width of the tarsus. The differences in the Riverside pair are definitively obvious.

From this, there is the very good possibility that the female has nested before, but who knows where. The tiercel almost surely has not. There are just a few cases where an immature Red-tail has mated while still in brown feathers, in the spring following its hatching. . .

Sadly, for the Red-tail and other similar hawks that were never used in classical falconry, there is no really fine, deliberate designation of a female. A good number of falconers and raptor biologists label a female Red-tail as a "hen." For me, that's a term that should be reserved for real hens, female adult chickens and other closely related species. For me, "hen" is not properly serious enough to be used for a female Red-tail. To me, they are never so diminutive as to be called a mere "hen."

I'm therefore stuck with "female." I've lost a bit of sleep on occasion, trying to summon appropriate neologistic powers and fabricate some new word for a female Red-tail. No luck.

I'm open to suggestions. This is a linguistic hole that needs to be filled, although I'm not certain that these gaps are ever sufficiently filled by anything than other than normal conversation among aficionados, over decades.

Anyway, the Riverside Park tiercel is nesting for its first time.

--John Blakeman