Thursday, September 27, 2007

Red-tail Signals Part 2 and More From John Blakeman

What was it I was looking at in yesterday's photographs? From the ground it is difficult to see what the hawks eyes are actually focusing on every second and as eye contact in birds is often taken as a sign of aggression, I'd incorporated that into my thinking and perhaps it was prejudicing my observations.

Pale Male often bows his head upon landing on the nest with prey. I'd theorized that he was pointing the meal out to Lola, but also that he might be avoiding eye contact with her so as not to cue aggression. That is if aggression were a wired in response to eye contact no matter who was doing it. he then would look in various directions being vigilant and then he'd continue to keep his eyes down when his face pointed her direction. (See yesterday's photos in the next entry down.)

Note in the photo above that Pale Male points to the prey by focusing on it but Lola is still looking out, not at him or it.

After his vigilant looks around he is pointing/looking at the prey again and this time Lola is looking in his/the prey's direction. (Wish I could see which it was.)

After more vigilance, Pale Male is now looking at Lola as if to say,"You've seen it?" Now the question is whether her "answer" yes, is a look on her part at the prey as he looks at her or whether they actually make eye contact. There may also be signalling going on between them about her leaving the nest for a comfort break during this as he repeatedly looks out more often than the other directions---but one thing at a time.
And John Blakeman's response to my entry about Red-tail cognition--

First, I'm not really familiar with any of the signaling behaviors you have mentioned. And I don't think any other student of the wild red-tailed hawk is, either. None of us who study red-tails in the rural wild have the opportunity to so closely observe these behaviors. Out here in the countryside, we can see a red-tail nest, and often the sitting female. But the nest is usually tucked back into the foliage of the tree, and it’s typically three-quarters to the top of the tree. We haven't the convenience of an open nest on a building as you do in Central Park and other parts of NYC. Red-tail behaviors, curiously, are much more difficult to closely study out in rural areas.

The birds fly around on the edges and margins of the local forest or woodlot, contrasted with much more visually accessible flight and perch patterns experienced in Central Park. Frankly, it’s tough out here to observe all of what you describe.

I've mentioned before the unique and favorable opportunities for detailed studies of red-tail nesting habits in NYC, however adapted to the urban environment those might be. The intimations of behavioral signaling between Pale Male and Lola that you mention are, for me (and I would suppose most other red-tail scientists), unknown or undescribed.

For example, you and others have noted frequent food caching. This is well known for the falcons, but very poorly described for red-tails. Actually, I've never seen it with my wild rural birds.

But I'll bet it happens much more frequently out here than we would have thought. I think it probably occurs most often when prey animals are frequently seen and captured, as in Central Park. That may account for the frequency of this behavior in NYC. I may not have seen it out here because prey animals are less frequent and much harder to capture here. Captured animals are summarily consumed when taken. There is no surfeit that can be parked in trees for future or shared consumption.

None of this addresses, however, the question at hand. Do red-tails have more complex signaling or communication abilities than I've attributed to them? I've contended that red-tailed hawks are clever, deliberative, and opportunistic hunters, spending great amounts of time “calculating” how to hunt and capture prey. But I don't extend these higher intellectual powers to any of the species’ other behaviors.

I contend that everything else the hawks do is based upon very primal, ritualistic behaviors. Effectively, the birds merely “go through the motions,” following ingrained hindbrain reflexes or patterns. They are thinking, but not creatively or intuitively.

Do the birds of falconers have reduced intellectual powers because they were removed from the wild at an early age? I'm certain that this is not a factor. First, virtually no falconry red-tails are taken as eyasses from the nest. Falconers (and raptor rehabbers) are well aware that young red-tails simply don't make good falconry or captive birds. They too easily confuse the falconer or rehabber with their parents and fail to learn to hunt on their own. Falconry red-tails are taken in the fall migration, after they are no longer dependant on adults for food and after they have learned to hunt on their own.

I've released trained falconry red-tails back to the wild, and they survived and thrived well on their own. Their behaviors weren't warped or deficient. Most of the peregrines originally released to create today’s wild breeding populations were raised in captivity using falconry techniques. They've done well in the wild.

The degree of red-tailed hawk intellectual powers is still an open question. Too bad that there aren't any real red-tail behavioral studies being conducted on NYC pairs. The opportunities to parse out these questions is great.

--John Blakeman
(Folks, I haven't forgotten about the mystery bird that looks like a Magpie without black wings. We'll get there soon. And many thanks for the emails concerning her ID.)
Donegal Browne

No comments: