Monday, February 21, 2005

Many new items below including FOUR new letters from John Blakeman

2/21/05 --Many new items below including FOUR new letters from John Blakeman



Here are my requested thoughts from your very interesting post.

First, don't anyone apologize or diminish any of their own thoughts or explanations on this. I may be some kind of red-tail “expert,” but everyone should question, or at least remain open, about most of what I contend. If I had time, or were writing a book on the matter, I'd delineate what I perceive to be “fact,“ as opposed to my evidence-based prognostications. Most of what I post is pretty sound material (in my mind and experience), and I would be able to defend those notions with abundant evidence. Other thoughts are just those, mere thoughts.

I'm taking the liberty here to lay out all of my thoughts publicly, allowing everyone to follow the development of my personal explanations for the Central Park red-tailed hawk saga. In strict science, all of this should remain obscured, to be revealed only upon the publication of a paper. But here, we are carrying on a must delightful public discourse, and all thoughts should be out on this expanding table of ideas. Again, don't anyone be reluctant to offer his or her thoughts and observations.

I still contend that most of the red-tails fledged at 927 Park Ave never attained adulthood. Why do I believe that? Because that’s the case with every studied population of immature red-tails. The banding data overwhelmingly support this, and I've watched any number of mid-summer red-tails get pushed out of their natal territories in July and August. I've trapped these birds for banding, and they are extremely weak, approaching starvation.

The following explanation would be far too long to entirely describe, but let me just touch on the survival challenges that must be met by a young red-tail who, for the first time, is no longer being fed by mom and pop. The first challenge for a youngster first on her own is to actually find food. Yes, red-tails have remarkable eyesight. Innately, they can focus and peer telescopically with great resolution. That’s all fine. But they actually have no innate or instinctive capabilities to actually find where food exists. They have to learn where and when mice, voles, rats, and other potential prey can be both seen and captured. This can take weeks to learn.

Next, the inexperienced hawks have to learn how to capture the prey. This might seem to be the least of their problems, given their strong talons and wings. But no one more than falconers knows how clumsy and inexpert immature summer red-tails can be in actually grabbing food. The hawk has all the equipment, the talons, the strong legs, the powerful wings, and telescopic eyes.. But until all of these are perfectly coordinated, hunting efforts are profoundly inept. I've seen this awkwardness in many summer-trapped falconry hawks. Many of these, I'm sure, would have starved had I not trapped them and started to train them to hunt successfully on their own. While in this falconry training, I provided the food they could not capture on their own.

Lastly, a kicked-out August or September young red-tail has to also find a vacant habitat where it can perch, hunt, and roost. In August and September, adults don't want any young birds in their territories because for the first time all summer, prey becomes harder to find. But late summer, there aren't anymore young robins, rabbits, or other abundant, easy-to-catch prey. In May and June, the days are long (lots of hours to hunt), and vulnerable prey are abundant. None of that’s the case in August and September, when the majority of young red-tails perish.

So, I still firmly believe that the majority of the eyasses sired by Pale Male never attained adulthood. They never lived long enough to molt out a red tail in their second summers.

But right here, I'd better inject an alternate explanation about the possibility that the pale-headed red-tails seen in Central Park might be 927 progeny. Elsewhere, I elaborated on why these birds are not likely to be so, based upon general red-tail biology and evolutionary tendencies. I still think this is the more likely explanation, that the new birds’ parents are not Pale Male, Lola, or any Pale Male’s other consorts.

But if Central Park today can support three nesting pairs, along with the recently-observed five immatures – 11 hawks that have to each capture and consume about 120 grams of flesh every day – then, perhaps, Pale Male and Lola haven't been very astute in driving off their youngsters. If Central Park has a continuing abundance of food, perhaps, then, the young weren't driven off. I continue to believe that most still died from hunting inexperience. But I have to now admit that there is a greater possibility that at least some of the other Central Park red-tails might be 927 offspring.

For those who might see this as a wonderful, romantic turn, I assure you it’s not. The constraints of genetic non-variability or uniformity would still be detrimental, especially if the Central Park red-tailed hawk population were to begin to inbreed. If that’s so, if most of the CP red-tails descend from a single parent (the great sire Pale Male), things could get very ugly in just a generation or two. The first thing to go wrong would probably be behavior fitness. Inbred hawks would be less likely to learn to effectively and safely hunt. Secondly, they most likely would not go through all the nuanced rituals of pair-bonding, nesting, and the successful rearing of offspring. Getting all of this just so is a remarkable ballet, one that everyone is watching once again. It doesn't take much to upset the successful but delicate interactions between both mated adults and their offspring. By nature, these birds are quick, muscular killers. All of the mating, copulating, incubating, and rearing behaviors of nesting pairs is contrary to the birds’ innate, day to day nature. I fear that inbreeding would easily disrupt this delicate balance between the restraints of pairing and the killing instincts of normal, day to day life.

It’s easy, even convenient, to believe that all of what were are seeing is the real nature of the red-tailed hawk. The birds appear to be loving, devoted mates and parents. These they are, of course. But how many have seen a red-tail actually hunt down and brutally kill a rat or pigeon or squirrel? To see this close at hand, as I have so many times when my falconry red-tails have taken cottontail rabbits, is to fully understand that these birds are carnivorous predators. They are, by nature, killers, ever bit as much as the lions of the African plains or the brown bears of Alaska.

On another point, I don't believe Pale Male is an evolutionary breakthrough. He’s nested for over a decade; a nice achievement, but one shared by thousands of other red-tails. His nesting record is quite typical for the species. On the other hand, he certainly has learned to succeed in the unique environment. But this, alone, is not so remarkable because the species itself has learned to live in so many habitats. The red-tailed hawk lives and successfully breeds in virtually every habitat (except closed forests) from the edge of the Arctic all the way to the Mexican desert. In the West, it nests on cliff sides structurally not much different from 927 Park Ave. Pale Male’s ability to adapt to NYC and Central Park, I believe, merely reflects the general adaptability of his species.

Once again, banding of the offspring, to allow accurate identification, would bring real light to this question.

Let’s hear the thoughts of others.


John A. Blakeman



Lisa’s remarks on the role of the “essential oils” emanating from the pine needles are significant. I thought about her comments, and this came to me.

Red-tails that aren't incubating spend up to an hour or more most mornings preening. In doing so, they transfer oil from a gland on their rump to the feathers of the body. Hawk watchers can often see this. The bird pokes her bill down into the feathers of her upper rump, where she gets a microscopic layer of the feather oil on the beak. She then strops the oil-laden beak on feathers all over her body.

This daily feather maintenance is absolutely essential. Remember, on the wettest, windiest days, our red-tails aren't passing the time inside any dry shelter. They are stuck out there in all of the worst weather, and if their feathers aren't properly oiled, rain will soak through and quickly kill the hawk by hypothermia. Daily preening is not for beauty.

Like most birds, our hawks are similar to turtles, in that they carry their houses with them where ever they go. Their houses, of course, are the feathers, which keep heat in and water out.

How might pine needles be involved in all of this? Lisa’s thoughts are particularly cogent. A sitting, incubating red-tail does, indeed, preen, but she can't spend an hour on her feet doing this. She’s pretty much bed- or nest-ridden. She still has to get the oil from her oil gland out over her feathers. But because she has to spend most of her time with her naked belly skin (the brood patch) tucked right up to the developing eggs, preening time and effort becomes a bit problematic.

Here is where the pine needles might enter. When red-tails preen, they not only spread protective feather oils, but they also comb out with their beaks very tiny feather lice. These very tiny bugs actually eat hawk body or contour feathers. The feather lice prefer to eat the white, un-pigmented portions of the brown body feathers. Preening greatly limits the damage feather lice can cause. The aromatic emanations of pine needles might restrict the feather lice while sitting on the nest.. Therefore, the sitting red-tail can apportion her meager preening time to only spreading feather oil. With the pine needles, she perhaps needn't spend much time combing out the feather lice. The pine needles may drive the lice away.

Red-tails have another arthropod ectoparasite, the hippoboscid fly. I have never found one of these large, slow, flattened flies on a healthy adult.. But virtually every immature bird has them. These things are the size of large house fly, but are very flattened. They don't fly very fast, but they move between the layers of feathers with great alacrity. These things live on blood they suck from their hawk hosts, and can be a real problem when the young red-tail begins to decline due to poor health or starvation. A healthy, experienced adult learns how to grab and kill the bugs with their beaks. But the newly-fledged youngsters don't recognize the pest, and they can run rather profligately between the feather layers. A single dose of parrot ectoparasite spray kills the hippoboscids in my captive birds. They never come back. The aromatic gases or odors coming off the pine needles may drive the hippoboscids off the incubating parents. They surely don't have much time to be poking around with their bills chasing these feather flies while still trying to maintain proper temperatures in the eggs beneath.

This would be a wonderful experimental study by an undergraduate ornithology student. Devise some trials where pine needles are placed next to cultures of feather lice and hippoboscids and record their reactions. This may solve the “Why evergreen sprigs?” question. Good thinking Lisa, something I hadn't considered.

One last note. For those watching the birds up close, check to see if the bird you are watching has evidence of feather lice. On first year birds, every single one of them does. Look on the brown contour feathers of the back. You will see that the margins of these are quite irregular, as though they've been eaten away. They have been. The feather lice eat away the white parts, leaving a very irregular brown edge.

Then look at the same feathers on any adult. You are likely to see some irregularity, but much of the whitish margins of these feathers will be unconsumed. The adults stay ahead of the feather lice. The youngsters aren't good at it. This is often an indicator of a hawk’s general health. Those in poor health or nutrition are badly feather eaten. Survivors have the lice, but with markedly reduced damage.

And for anyone concerned that these little arthropods might have jumped off my captive birds and infested my person, don't be alarmed. These very tiny bugs are absolutely confined to buteonine hawks. They couldn't even survive on the feathers of a pigeon or robin, let alone on human hair. The feather lice of my beloved red-tails pose no danger to me or anyone else. They stay on the hawk, or die.


John A. Blakeman



***Dear Marie...Just one thought still puzzles me, and that is the apparent, strange "tiptoeing-around" the vernaculars used to depict the actions of the Hawks. Why must this be? ALL language was, in fact, created by PEOPLE! Even scientific terms were created by people. So, if some people chose to describe Pale Male and Lola's actions as "Mating," this seems perfectly fine to me, since mating is a word commonly accepted in our society to cover a broad spectrum of phases. So, if some of we people refer to romance, breeding, mating in terms poetically pleasing, all the better. This is why we have the Theosaurus. I'm sure these scientific terms are meant as guidelines, not decrees. I guess if one were to follow that course, what lies ahead? Babies referred to as "plasma-multiplicands" or something? Please, please...let's have everybody create and express life as they individually feel without fear of not being "scientific enough." I really can't see a world bound by these strict guidelines as to how you are to phrase things. There should never be a need to apologize for creative expression as long as it is for benefit of all living things. Be free everyone, all of you who have written such wonderful works, those who have been so stalwart in your prose and as such,earthly stewardship of all living things! Amanda

***Dear Marie,

My take on "Mate" Vs. "Copulate" is that they are usually synonyms. "Courting", or "Courtship Display", however, is alway the activity that leads to "Mating" and/or "Copulating". What muddies the water is the unfortunate terminology: "Mating Displays" used as synonym for "Pair Bonding" and "Courtship Displays". But, the "act of mating", or the "mating act" means one thing and one thing only=copulating, joining, coupling or whatever four-letter word you like.

Best, Katherine Herzog

***Hi Marie—

For those who don't feel comfortable using the word copulation, how about the most popular euphemism used by humans (at least when they are in polite society) to describe their own activities: "having (had) sex." While it isn't scientifically correct, I don't think it would be considered incorrect either. And it has the advantage of not being the biological term for another activity.

—Susan Keiser


I live in Atlanta and have followed the story of Pale Male from here. Tonight I was looking at when I came across the following post,

"The hype in New York about "The Gates" has been so pervasive that I am delighted to read some cool and skeptical responses. As a New Yorker, I have been subjected to the hype, but I joined the throngs in Central Park so that I could test my own skepticism with actual experience. With all love and deference to my friends who are flying into NYC to walk under the saffron pleats, I find "The Gates" a Disneyland for a cultural elite. A relevant footnote: I was caught in gridlock near a gate in the southwestern part of the Park. Everyone was staring at a tree branch over the artwork, where Pale Male, a famous local falcon, was chomping on a small animal. The crowd was discussing, not the Gate, but whether the animal was a rat or squirrel. Reality bites."

Who knows if was really him.




About Karen Anne Kolling's incisive questions about what really constitutes "territory" in the case of CP red-tails.

In the rural wild, all of what I noted before is accurate. Wild rural red-tails simply occupy one or two square miles (or more) and drive off any other red-tail that might enter this space. There isn't enough food for three birds in the territory, so the odd bird is driven out. Period.

But this usual arrangement is in flux in CP. Lots of food, lots of hawks, and small, even undefended territories. The area around the nest is the actual territory. The only question is the radius of the territory. It's a mile or two in rural areas. Right now in CP it seems to be variable and indeterminate. We'll just have to see how this plays out. I've never seen this before. This may be unprecedented in red-tailed hawk natural history


John A. Blakeman