Friday, May 05, 2006

Do Redtails form a bond to their young? John Blakeman answers

Pale Male & Lola, still attending nest, May 4, 2006
Photo by Lincoln Karim

Today a letter arrived from a website reader; I promptly forwarded it to John Blakeman.

The recent letter from John Blakeman was very interesting and brings to mind a question.

On the one hand Mr. Blakeman has observed a wide variety of emotion from Red Tails and on the other no emotional attachment to eggs or eyass's. What I'm wondering is if the parent RedTails ever develop any kind of bond to their young, perhaps shown during times of first flight or later on as the grow, or do they always act like its a job and things get easier for the parents on the young grow up and eventually leave the area. It seems from a strictly survival point of view such an approach would be best for the species.


Karl Nicholas

John sent the following informative, hard-hitting response :

Karl's question is a good one. If red-tails can get rather animated, even downright "emotional" in their hunting, how is it that they don't express much emotion toward their young? I've said that adults' behaviors toward their eggs and young are rather mechanistic and not thoughtful in any mammalian sense.

Let me try to explain in more detail. We falconers are always amazed at the behaviors of nesting raptors. They are so different, even aberrant, from what these predators do for a living. All of the behaviors associated with red-tail nesting, from copulation, to nest building, to incubating, to feeding eyasses, and lastly, to tending newly-fledged eyasses, are all in conflict with red-tails' normal, day to day behaviors and views on life. Let's be clear. These birds are predators, profound killers. They make their living by successfully and repeatedly killing other animals. Any red-tail that fails to learn how to kill soon dies. Forty to sixty percent (or higher) of fledged red-tail eyasses never attain adulthood. Most die in their first summer. They fail to learn how to hunt and kill.

A red-tail's life is not dependent on mating, copulating, nest building, incubating, or tending eyasses. The hawk's life depends on its ability, throughout the year, almost every day, to find and kill other animals. That's what every red-tail is programed to do. Just as a four-year old boy is programed to throw things, in order to make the baseball team, the little tike will have to grow up a bit and practice, learning how to accurately throw and catch a ball. The young red-tail, in a few weeks in summer, must learn how to hone her instinctive hunting desires into refined killing techniques. A few red-tails learn these skills every year and later become adults. Most fledged eyasses, however, fail to learn the killing lessons and don't get a contract for living after August or September. They just starve.

Can you see that the behaviors of daily survival -- hunting stealth and killing -- are completely at odds with nesting, incubating, and eyass feeding ones? If I were to toss a young chicken hatchling beneath my falconry red-tail, she would kill and eat it in a second. But on the nest, a sitting adult does not consume the new little eyass. But it's no different from a wondering duckling that has just hatched. The hawk will kill a young duck instantly. Location is everything.

It's interesting to watch how red-tails change -- by instinct -- their behaviors around and on the nest. Other raptors do this too. Within a few hundred meters or so of the nest, red-tails' hunting desires are somehow turned off. By instinct, they are prohibited from killing anything near the nest. This keeps them from grabbing one of their own eyasses for a quick snack. While on the nest, they often fold under their sharp talons so as not to puncture the egg.

We falconers are always astonished to watch a red-tail (or peregrine, or any other raptor) feed their eyasses. It's against their everyday common behaviors, and it's all controlled by sex hormones. In the spring and summer, with expanding day lengths, the birds' aggressive behaviors at the nest are turned off. If a red-tail could think while tending a cute little eyass (she can't), I think she would be asking, "Why am I doing this? This little thing moves around and is really a nice meal. Why can't I just reach out and kill the thing and eat it?"

She can't because her reproductive hormones have kicked in a whole new set of restrictive behaviors, none of which result from thoughtful decision making or other cerebral activity. The hawk is just going through the motions. Don't even think about killing anything within a few hundred meters of the nest. Don't grab anything that moves. Drop little pieces of meat down the open throat of the bobbing eyass. Sit on it and keep it warm.
In summary, the otherwise "emotional" behaviors or thoughts of the adults are really mechanistic, instinctive behaviors. If there is a round white object there, sit on it and roll it around a few times every day. The 927 pair are still following these hormonally-driven behavioral prompts. Not until they get tired of it, only when it gets very old, will they stop. They are clueless about what they are doing. They are not waiting for the eggs to hatch. They are merely sitting on them because they are programed to do so, period. There is neither joy or lament, just instinctive behaviors that are so contrary to what they do "normally."

Normally, red-tails sit around and think about how they can easily capture another animal. Here, they calculate and plot. They learn what hunting methods work and don't work, which is one of the great stories about red-tails in Central Park. No falconer or raptor biologist would have predicted that red-tails could have so successfully inhabited Central Park because the hunting techniques they learn and use in the wild shouldn't (and wouldn't) work in the city. But these birds have thoughtfully learned to successfully hunt and kill, and we therefore get to experience them in the heart of one of the world's great cities.

Red-tails are thoughtful and emotional in hunting and killing -- in daily life. They are not so in nesting. To be successful nesters, they must turn off their normal emotions and go into a behaviorally restrained, leave-it-live mode of life. It's the lack of "emotion" that allows the species to breed each year.

--John A. Blakeman