Sunday, September 25, 2016

Why does the hawk screech?

The red-tailed hawk has a great cry, or call, or whatever it is, which is something of a mystery. We hear it fairly often and call it a shriek, but it is generally known as a scream or a screech. You can hear it here:

The interesting thing is that no one is sure why the hawk is doing it. In fact the explanations tend to be contradictory. Sometimes it is said to be territorial, warning other hawks away. But then it is said to be a warning cry, but warning who? Other hawks? It seems to have been observed in both uses.

Another possibility is that it is a sort of a warning to something it might attack, that is a threat of sorts. My wife once came too close to an eagle's nest and was warned off by the eagle screaming while hovering over her. It was very effective.

But recently I observed a hawk screeching that seemed to fit none of these modes. I first saw it flying low over the horse field, shrieking as it went. It then landed in a tree, where it continued to call. This calling then went on, off and on, for over two hours, from various locations.

It is late September so there is no nest to guard. Nor does this seem like driving off a threat, because the hawk was all over the place, as it were. We only see or hear hawks very intermittently, so defending a territory seems unlikely. I suppose one possibility is that this was a juvenile hawk, marking out a territory for the first time, or some such, but that is a stretch since the migration is nigh.

So I am inclined to think that we just do not know what it was doing. The primary study on hawks appears to be this one from 1946:

But as the authors point out, this is a very specialized environment, where the hawks are closely packed. Territorial fighting is common, often carried out by mating pairs. We are more at the opposite extreme, in a national forest where the only open ground is the scattered valley farm. We only see hawks from time to time and seldom see two red-tails at once. I doubt there are any territories here, but in any case the protracted behavior I observed the other day was nothing like what the authors describe.

So we have yet another mystery, in this case a rather loud and entertaining one.

Saturday, September 3, 2016

How to do animal cognition research our way

One need not know anything about robotics to do the kind of research that I am describing here on this blog. The basic questions are these:

1. What decisions does the animal make in doing what it does?

2. What does the animal have to know or believe in order to make these decisions?

3. What concepts does this knowledge include, especially concepts that humans may not have?

Note that many human concepts are associated with language, but in animals most are likely perceptual in nature. For example, the animal sees that X, or looks for X, thus has the concept of X.

Just as I can search for something, animals do not have to perceive something at the time in order to use the concept of it. Horses going to a different field or a bird retrieving nest building material, for example. These animals are thinking about things that they cannot see at the time. Thinking ahead, as it were.

So our kind of animal cognition research is just a matter of thinking about the specific decisions and knowledge that the animal's behavior requires. A cognitive time and motion study, if you like, breaking the behavior down into its components and analyzing them. What are the steps? What decisions does each step require?

Of course one first has to know what the animal is doing and this can be a challenge. We often see the crows doing things that we do not understand, such as flying in a group from one place to another. But this is true of any science; one must correctly characterize a phenomenon in order to explain it.

In any case the point is that just because the behavior involves an instinct, this does not mean that no thought is required, quite the opposite. Instinctive behavior often involves expert knowledge, including complex concepts. It has to.

There is nothing anthropomorphic about this. A given behavior requires specific decisions and knowledge on the animal's part. It is as simple as that.