Saturday, August 13, 2005

City hawk kids are different than their country cousins: Blakeman

The photos of the two immatures "playing" are most interesting. For those of us who know the species in the wild, the birds' tolerance of nearby humans is remarkable. The Central Park red-tails regard humans very differently from their wild cousins out in the countryside. I'd be fortunate to get within a hundred yards of a wild red-tail. Here, the little tikes cavort together within a stone's toss of the hundreds of humans in the park. They don't regard humans there as much of a threat. Very nice.
But I was interested in the spread-wing postures of the two "playing" birds on the ground. One bird, with its wings elevated, is also sitting back upon its tail. This is usually done to allow a defensive forward thrust of the legs, to fend off the adjacent interloper. In the upper photo, both birds have assumed this combative posture. Altogether curious. I can't readily explain this, as I've never been close enough to watch any wild hawks engage in such behaviors.
I noted with interest several of Lincoln's recent photos, where the immatures exhibited rounded, or nearly full crops. It is very clear that these birds are getting an abundance of daily food. My concerns that things would get tough for them in August is (once again) unfounded. These birds are not much motivated by hunger. They are extremely well fed and their "play" is prompted by instinctive but immature reflexes, not by deliberate attempts to kill or gain food.
For this red-tail pair, all is going exceptionally well. That seldom happens with golden eagles, however. Golden eagles commonly lay two eggs, and both hatch. But in virtually every case, the larger eaglet will reach out and kill its slightly smaller brother or sister while still on the nest. This is known as the Cain and Able Effect. It happens with golden eagles and some other large raptors. Bald eagles, like red-tails, are more accommodating of siblings and seldom kill each other.
Sooner or later, the two Central Park immature red-tails will have to get off the ground and begin some serious hunting on their own. Right now, they are living rather carefree lives of prey abundance. Let's see when or if this changes.

John A. Blakeman