Monday, March 21, 2005

Falconry, Sexual Dimorphism and other Mysteries

Hi Marie,

I have a question raised by John’s wonderful letter today -- we all know that his ‘Savanna’ is a female red-tail, or ‘hen,’ but he made other references to the fact that he has worked with several red-tailed hawks -- and they all were referred to by him as female. Are female hawks merely his preference (and why)? Or in training hawks for falconry, is the use of ‘hens’ preferred in general? And why, (of course)?I’m sure other people have noticed this and raised this question!!

Thanks Marie and have a wonderful day!


Here's Blakeman's answer to the question:


Yes, I tend to work with red-tailed hawk females, "hens" for lack of a better term. This is for several reasons. The first is that more females are fledged than tiercels, for reasons no one knows. At least 60% of all fledged red-tails are females. Tiercels aren't equal in any way with the big females.Hen red-tails, as in virtually all other raptors, are markedly larger than the males. In fact, that's the origin of the term 'tiercel," an English corruption of a 16th-century French term meaning "one third." Peregrine tiercels are about one-third smaller than the falcons (the females).No one has come up with a good reason for the greater size of raptor females. In fact, it makes no sense whatsoever.

While big Lola is up there whiling away her many hours of motherly incubation, our patriarch Pale Male must be out on the hunt, not just to feed himself, but also his larger sedentary mate. His hunting prowess must more than double, although he is the smaller and less muscular of the pair.

The smaller mate should get the incubation task, but universally across all raptor species, the diminutive male is genetically assigned the daunting food provision task.And it gets even more difficult after eyasses hatch. The tiercel then must feed not just himself and his sitting mate, but also bring to the nest sufficient food for the rapidly developing eyasses. The tiercel has to spend virtually all daylight hours in late April trying to find, capture, kill, and transport food for everyone in the family -- a daunting task. (See why it's important to know the daily caloric requirements of adult hawks?)

Why the tiercels aren't the larger bird, more capable of attending to the demands of family food supplies during incubation and eyass brooding, is a complete mystery. I've utterly given up all thoughts on the matter. There are some ecological questions that may never have answers. This is one of them.

But why do I refer to every hawk except Pale Male with the feminine gender? It's an ancient convention of falconry, deriving from the abundance of hawk females in the wild, and their preference in the sport. Because hawk females are larger, falconers for centuries have preferred them over tiercels. Now don't misinterpret this. Tiercels can make exceptionally fine hunting birds, as with a remarkable red-tail tiercel captured and used by my current falconry apprentice here in Ohio. He has done notable things with this bird, and it holds its own against any prey it chooses to pursue, primarily cottontail rabbits. It just completed a very fine hunting year, and just "went up for the molt." It is being retired to the mews where it will sit contentedly and grow new feathers until autumn. (Incidentally the place falconers keep their hawks is called a mews. The Royal Mews of Buckingham Palace today houses the royal carriages. In former centuries, it housed the King's falcons.)From all of this, falconers simply refer to any hawk of unknown sex as a female. It is a matter of respect and honor.

Tiercels have their place in falconry, but the big females are most highly regarded. (And the greater presence of females is one reason that falconry has persisted for several millennia without reducing wild raptor populations. At the height of Renaissance falconry, in Shakespeare's time and the century following, there were 600 or so known peregrine eyries (cliff side nests) in Great Britain. One or two falcon eyasses (females) were removed from each of these every year for royal falconers for several centuries without diminishing the wild population. That's because an abundance of females is always produced, and just like the red-tails that have colonized Central Park, these excess falcons would have died without progeny in the wild, for lack of un-occupied nest sites after reaching adulthood.

For red-tails today, the same thing happens with the very few falconers in the U.S. We much prefer the giant females, and often refrain from taking a rarer male. European and American falconry has never had any impact on wild raptor populations except for the positive, as in raptor education and captive breeding of peregrines, etc.So, if you see a red-tail sitting in a Central Park tree, it's a she, unless you can surely tell otherwise. It's a matter both of convention and respect.

John A. Blakeman