Friday, June 18, 2010

John Blakeman on how hawks hunt and kill

John Blakeman, master falconer and raptor biologist from Ohio, has been so generous with his expert knowledge for the Hawkwatch blog. He has provided us with a master class in red-tail hawk behavior at every step in the progress of the Franklin Institute eyasses and their parent haggards, and recognizes the unique nature of the Franklin Institute nest

Here is his latest commentary on how hawks locate, catch and kill their prey, illustrated with some of Kay Meng's images from last year and this of the Franklin Institute haggards.


"Those fortunate enough to intimately watch the activities of haggards and eyasses at red-tailed hawk nests such as at The Franklin Institute see much that others never get to experience. I thank the Institute for allowing all of us to be so keenly entranced with this remarkable spectacle.

I’ve been studying red-tailed hawks across the entire continent, from Alaska to Maine for 40 years, focusing primarily on the birds in my native northern Ohio. I’ve watched dozens of nests, and except for a few in northern Nevada, where I could look down into the cliff-ledge nests from above, I’ve never been able to see all that I’ve seen now for two years at The Franklin Institute. My great thanks!

But there is one facet of red-tail life that has not been observed at The Institute nest. It’s extremely important, and to understand this regal bird, this facet of its life should be understood and pondered. I believe I know it better than most raptor biologists because I’m a master falconer, and I hunt with red-tailed hawks, so I get to see what I’m about to describe first hand – up close and personal.



The topic is how the hawks find, capture, kill, and eat their food. It’s not like a pigeon finding grain or seeds, or a robin pulling a worm from the soil. It’s far more complex and interesting; if not gory and startling. This may not be for the squeamish. We are dealing with a predator, a species whose life depends upon the slaying of other lives. A very serious matter, both ecologically and morally.

A more exhaustive deliberation on these topics should be the themes of several chapters in an intended book on red-tailed hawks. But in the shared joy of The Franklin Institute fledglings, I’ll focus on what these young birds must learn in the next six weeks or so—how to hunt and kill, efficiently and frequently. Should these skills fail, the now-healthy eyasses will starve and die this summer, a fate that awaits the majority of fledged red-tail eyasses. This is a serious matter, much more so than merely learning to fly and land.

First, let me summarize the hunting and killing skills and protocols of the haggards. They are profound killing machines, resulting once again in the production of three fledged eyasses, which are a result of the haggards’ applied hunting and killing skills. Our three eyasses never once went to sleep hungry. They grew and thrived on ample and diverse food brought to them by the haggards, but mostly by the tiercel. He was a father supreme, in every respect, the Great Provider for both his young eyasses and his incubating and eyass-tending formel. Let’s start with just how the tiercel was so able to provide food for his large family.


To capture prey, the hawk must first spot it, using its telescopic eyesight. That’s pretty obvious. But a more subtle, but even more crucial factor must first come into play. The hawk can’t spot prey animals that aren’t there. The first big factor is for the hawk to Be There. Where? Where prey are likely to be seen.


Our vaunted tiercel did not spend the winter and spring wandering randomly around his portion of Philadelphia. Quite the opposite. His flying traverses above the Parkway trees and buildings were anything but random. When we see a red-tail regally coursing overhead, we have no idea what he’s thinking, or where he’s going. To us, he’s just flying around up there. Looks pretty relaxed and casual to us, something we’d all like to be able to do.

Many a time I’ve imagined myself as a red-tail floating on set wings above my rural landscape. What wonderful views I could have, how much fun it would be to set my wings against the winds and get caught up in a warm thermal draft over a nearby soybean field. In just a few minutes, without a single wing beat, I’d be at 3000 feet, peering down telescopically at everything below. I feel sorry for those who have never watched a red-tail do all of this, as they’ve never personally entertained such dreams of emulating the hawk’s soaring flight. All of us need to engage in such fantasies from time to time. They allow is to connect so personally with these regal birds.
So, no - red-tails circling high above, or flying just above the trees in a straight line, are not randomly wandering. Each of their movements are somewhat deliberate, performed within a guiding mental framework of experience and desire.


When red-tails are soaring, they are never hunting. They soar because they and their eyasses are fed and sated. Although it’s unacceptably anthropomorphic to say this, I actually believe that red-tails just love to soar and circle as we would ourselves, were we given such powers. Hanging up there so effortlessly and wheeling so balletically must be pleasurable to these birds. They are content, secure, and hopeful in these elevated flights, if not downright ecstatic.

But red-tails, and all other hawks, are visual creatures, seeing things that few other animals can or do. They are able to see broad, but detailed, wide-angle fields of view just as we do—and very few animals can do this. We have a giant portion of our brain, the occipital lobe at the back of the cranium, dedicated to the interpretation of the massive signals coming into the brain from our dense light-sensing cells on the retina. Many animals are almost blind, lacking the ability to make sense of all the photos impinging on the retinal surface. Their brains focus only on a few, central details. We humans see better than most other animals.

And so do red-tails. They see the broad, wide landscape, perhaps almost as well as we do, although their brains are minute compared to ours. (That’s a problem for comparative anatomy and physiology, which I’m not competent to expound upon.) But here’s where red-tails and other similar hawks differ from us. As the hawk scans the sky and landscape, its brain instantly recognizes what’s most important - the distant appearance of a prey animal. A soaring peregrine falcon can spot a distant prey bird, perhaps a pigeon or duck, from thousands of meters away. A red-tail’s eyesight is just as good as a peregrine’s, but it’s searching for food it prefers, primarily prey on the ground, mice, rats, and squirrels. (Pigeons are an entirely other matter, which I’ll address later.)


As our tiercel flew all around The Franklin Institute last year, it was always searching for food to capture, kill, and eat. Here’s the important consideration of all of this apparently random flying around. First, again, it’s not so random. There is a daily pattern to red-tail flights. That’s why it would have been so fine to get a radio beeper (transmitter) on either of the haggards so their whereabouts 24/7 could have been plotted. When this is done (I’ve done it only by diligent visual plotting using a binoculars and a car, tagging behind a red-tail’s daily flights in my flat Ohio row-crop landscapes), red-tails are found to have a somewhat narrow schedule of daily activities, among which is a lot of flying from frequent perch to frequent perch.

Red-tails usually spend much more time perched than flying. To the unknowing, they are regarded as lazy sit-abouts failing to attend to important matters—living as many of us do too often (or wish we could, as on vacation). Not so, however. Get your binoculars on a sitting red-tail and look closely at what he’s doing with his head. Except when preening (usually in the morning—another topic altogether), he’s moving his eyes in every direction. He may have his foot propped up and appears to be at utter ease. Physically, he is. But mentally, he’s taking in everything he can see, focusing for an instant to the left, then to the right, then down below, then behind, then back in front. All the while, he’s watching for two things; first, the presence of any intruding red-tail or other hawk or unwelcome bird or animal. But more importantly, he’s looking for any prey animals, any animal in his giant field of vision that could become his next meal. His brain is exquisitely programmed to instantly zoom in on and focus on any potential prey animal that appears in his field of vision.


And every time he sees any such animal, even if it’s a fractional glimpse of a rat’s tail, a split-second leap of a one-ounce vole between two distant grass clumps, even the hop of a grasshopper one hundred yards away, he sees and records the image in his brain. His existence depends on these innate skills. He must quickly learn and remember where prey can be seen.
So as our Parkway red-tails have flow around their Philadelphia neighborhood in the last year, in all seasons and weather conditions, they have been diligently recording just where they’ve seen potential prey. That’s where they are going to go when they want to hunt, when they or their eyasses are hungry. They have learned to cogently read the entire landscape the occupy, and know exactly where the next meal’s most likely to be found.

That’s the first, and in fact, most important part of this story. The hawk has to put himself where he has the highest chance of winning, of seeing and capturing a prey animal. He’s got to get the odds in his favor. He, as the eyassses will in the coming weeks, learned that car parking lots, for example, just never have any huntable prey. Don’t waste time sitting on a utility pole looking down amongst all those iron heaps for a warm, juicy fresh meal. Wrong place. Fly over to where prey were frequently seen and caught, to happy hunting grounds, as it were.

Fortunately, there are apparently lots of good hunting areas for our red-tails on the Parkway. The newly-fledged eyasses will now have to learn those lessons themselves, using their still-weak flight powers, powerful eyes, and developing mental abilities.

This is getting a bit long here, so I’ll return later with more of this big story, how red-tail hawks hunt and kill."

-- John Blakeman

Thursday, June 17, 2010

Eyass action on Thursday, June 17

All three eyasses are now flying strongly on and off various perches and landing spots around the nest area. Carolyn Sutton and I were down at the nest early this morning. Here's what Carolyn observed:

"Got a late start today, so when I got to the nest, the eyasses were already on the move - one was on the south Civil War monument, one on was on the pediment of the Franklin Institute Winter Street entrance, and one was in a tree on Winter St. As I watched, that eyass flew over to the trees alongside Barnes construction site. Mom was.....guess where?.....atop her favorite construction site crane! The young hawks have upped the decibel level of their calls for food. You can now hear them above the traffic noise from way across the Parkway. The three little guys all flew to the facade of the Franklin Institute, then two moved up to the roof and one flew into the nest. Still no Dad and I had to leave. Luckily Della arrived to take up the vigil and I am sure will continue this update later." - Caroline Sutton


When I arrived on Winter Street, I immediately saw the eyass on the nest. It was calling out with that distinctive seagull-like sound that brought back memories of last year's eyasses. In the absence of Kay Meng, I chugged along with my little point-and-press camera, but if you look closely, there is a hawk in every picture!



As busy as it was calling out to the haggards for food, the eyass also was keeping an eye on what was happening on the street below.



One of the eyasses on the roof above the nest moved down to a lower ledge...



... on the 21st Street end of the Franklin Institute



A flurry of wing-flaps to the left caught my eye as a haggard flew towards the nest. Within a minute or so, the second haggard landed on the nest.



I looked over to the Civil War monuments, and there on the closest one were two of the eyasses eating breakfast from a food drop just made by one of the haggards now on the nest.



Actually, one of the eyasses was doing all of the eating, while its sibling watched hungrily. The size and shape of one of the back legs of the carcass led me to believe it was a rabbit.



Each time the foodless eyass made a move toward the food, the other mantled over its meal...



... then resumed gobbling down its breakfast.



Finally, it appeared to be sated, and allowed its sibling to move in on the remaining scraps.



And in the background, the huge cranes working at the Barnes Museum construction site, roared into action.


It was exciting to see all three eyasses flourishing, and so well taken care of by their parents.

Part 3 - Video of the newly fledged eyasses

Here is the third part of Karen McCunney's terrific video of the eyasses on their second day off the nest.

You can clearly see how close they perch to the multi-lane Vine Street Expressway underpass. On the positive side, however, this proximity to loud traffic 24/7 since they hatched has made them pretty impervious to any kind of scary noise.

Their flying and perching skills grow literally by the minute as they experience different landing challenges - iron railing fence, light post, stone ledge, wire construction fence. At one point, a fledgling attempts to land in a tree but is too close to the end of the branch which bends under its weight, resulting in lots of flapping before moving on to a thicker branch.


Wednesday, June 16, 2010

Eyasses out in the world

All three eyasses are adjusting well to life off the nest. Hawk watchers visit the Parkway area at all times of the times of the day and send back positive reports to the Franklin Hawkaholics Face book page. This morning, Carolyn Sutton was down there early, and sent these comments:

"Saw all five of the family this morning between 5:15 and 6:oo AM. The three young hawks first met on the south civil war monument, flying in from the nearby trees. Then one by one they flew to the Franklin Institute window and roof ledges, squawking all the while. Mom was there in a flash, but without food. It seems the family located the breadwinner before I did. Mom flew up to the roof where, lo, there was Dad with breakfast. Two of the youngsters followed Mom's lead, and managed to grab a few leftovers from their parents. #3 flies lower than his older sibs, so he was still on a low window ledge when I left. Dad took off to the west for more hunting, and Mom flew over to perch atop her favorite construction crane on the Barnes Museum site. By the way, the leftover bones Maryitis found yesterday on the base of the birds' monument cafe were still there."



The two civil war monuments have become the central meeting spot for the eyasses when daylight breaks, as Kay Meng's pictures show. As best we can tell, they seem to spending the night in trees alongside the Parkway.


The haggards regularly deliver food which the eyasses gobble down under the watchful eye of the huge carved eagle on the monument.....Big Mother is watching you?

The eyasses spend quite a bit of time on the ground, walking around, exploring their fascinating new world.



They are starting to learn to hunt, albeit mostly bugs and worms at this stage. This eyass is walking around the grassy area immediately under the nest, looking for something to eat.



Ah...got it!



And they are starting to show some hunting behavior - a big pounce for a small bug!



You can't hunt if you can't fly well, and learning to land on all kinds of surfaces is an important part of successful flying. So the eyasses are giving it their all!




Some landing spots are much tougher than expected after the flat surfaces of the ledge and the civil war monument.



But they are learning so fast.

Tuesday, June 15, 2010

Part 2 - Video of the newly fledged eyasses

This is Part 2 of the terrific video footage that Karen McCunney took documenting the first hour or so off the nest for the second and third eyasses.
It is extraordinary how quickly they adapted to sitting on railings above a six lane highway, a flagpole above a billowing Egyptian flag, and tree branches alongside the busy Ben Franklin Parkway.

Monday, June 14, 2010

Back to the nest for the night

All three eyasses are flying well and are exploring their world outside the nest. The parent haggards are in close attendance making strategic food drops.

The eyass that had difficulty on Saturday got it together on Sunday, though it still seems to prefer the ground. It is quite common for fledgling eyasses to spend time on the ground, climbing into bushes and trees. In this urban environment, however, that can lead to some hair-raising adventures as we saw on Saturday.

Yesterday, it found its way to the grassy area immediately under the nest beside the Franklin Institute. This is separated from the sidewalk on Winter Street by a low wall, so is safe from traffic. Kay Meng and her camera were right there, as the eyass resourcefully decided to take on this worm for a snack!




As twilight fell on Sunday evening, it was likely that this eyass was the one who gave nest watchers the happy surprise of seeing the nest inhabited again. The eyass seemed to be settling in for the night.



This morning (Monday, June 14) as daylight broke, the eyass was still on the nest.



It puttered around the nest pecking in the sticks, probably looking for scraps of food, then just before 6 AM, it stepped purposefully to the front of the nest, and was gone.


Carolyn Sutton was there this morning and sent this report:

"Just returned from a visit to the nest between 5:15 and 6:15 this morning. I saw all five hawks. #3 was still in the nest. The tiercel (Dad) was briefly on the Civil War monument, then on his favorite streetlight. The other two eyasses were in the same tree on far side of the Parkway. One of them made a trip to the top of the Civil War monument and back, then made a very serious hunting maneuver to the side of the Free Library, where it hooked its talons to the bird prevention netting that hangs over the facade. The formel (Mom) was there in a flash to make sure all was OK. Fortunately, the eyass extricated itself and then went searching for vermin along a ledge. When I turned to check the nest, #3 had flown. The tiercel (Dad) took off from the streetlight shortly after and headed in direction of the library."


On the Franklin Hawkaholic group page on Facebook, there is a wonderful - and ever increasing - collection of photographs from hawk watchers who have been visiting the area where the hawks are.

Sunday, June 13, 2010

Video footage of newly fledged eyasses Part 1

Yesterday morning, June 12, Karen McCunney took this video footage very shortly after the second and third eyasses fledged. The bird on the top of the monument at the start is the formel who is eating the remains of breakfast that she had just removed from the nest.

Then we see the two eyasses in a tree on Winter Street where they landed after their first flight.