Now that the eyasses have clearly left the nest and the camera at the Franklin Institute has been turned off, we are all wondering how long the hawk family will stay in this area, and whether they will migrate south for the winter.
John Blakeman, as always, provides us a fascinating response:
"Red-tails, particularly those in both my native Ohio and those being watched in Philadelphia, do migrate. The migratory urge is especially strong in first-year red-tails. In August, they will be essentially separated from their parents, although they may still reside in their natal territory. But sometime in September or early October they are likely to soar up on a thermal and notice the passing stream of other red-tail migrants drifting southward. One day an eyass will be seen on a common perch, but gone the next. It will have begun its first migration to some place further south.
The migratory urge is not nearly as strong in adults. Pale Male spends his entire life in Central Park, and the Franklin parents are likely to persist through the winter. Experienced adults tend to spend the winter when ample food is available, which is surely the case in Philadelphia. But if food becomes harder to capture, even adults will head south.
Here in northern Ohio and across the northern tier of states the deciding factor is the depth and persistence of snow. In northern areas that are snow covered during much of the winter, sustenance prey species of mice and voles cannot be seen under the snow. The hawks then fly south where there are no persistent, deep winter snows.
That won’t be a problem in Philadelphia. The Franklin Institute adults will almost surely hang around the nest area this winter, staying within a half-mile radius or so. They have everything that makes a red-tail happy - lots of food, good perches, and no hassles from humans or anything else. Ample food is the big thing.
But the eyasses will likely disappear in September or October, if not before. Any of them can get killed by crashing into a fence, getting struck by a car or truck, or by acquiring some lethal parasite or disease. About 60% (a guess) of fledged eyasses never make it through the first year. Perhaps a half of them die in their first summer, usually in late July and August, after the parents stop feeding them. They just plainly starve, unable to learn how to adeptly capture enough food. Nature is tough, especially for dumb, inexperienced young predators. Only a few survive to full adulthood. So don’t take any special lament when one of the eyasses is found dead. Sorry to convey this news, but it’s very, very likely to occur (albeit undiscovered).
Those that survive to early autumn will begin to have a strong urge to migrate south, promoted mostly by decreasing day length. This turns on the migratory urge, and when these young birds see other red-tails passing along overhead, they find a thermal and effortlessly wheel themselves up a mile or so. Up there, the urge to lean off to the south, along with the dozens of other red-tails and other hawks which they can so easily see up there is overwhelming.
By November, they will be anywhere from Virginia down to the Gulf Coast. They will search for food down there, and when the days start to get rapidly longer in March or April, they will reverse their migratory trek, heading back to the general area of their nest in Philadelphia.
And here’s where some significant science could be conducted at the Franklin Institute nest. It would be so good to get next year’s eyasses banded, both with conventional numbered aluminum bands, and also with separate, unique color-coded bands. If this is done, it could be determined if the birds come back to the immediate nest area, or just to the general area.
This is a contention in New York. There are a good number of new red-tail nests there, and everyone wants to think that these are all direct descendants of Pale Male. Maybe they are, maybe they aren’t. Only good banding can reveal this. I hope that all future eyasses at the Franklin Institute can be color banded. In a few years, this could answer a great question in red-tail biology.
–John Blakeman
Tuesday, June 30, 2009
Sunday, June 28, 2009
Where do hawks sleep?
Earlier this week, we had really severe thunderstorms in Philadelphia. I thought about the hawks in the midst of hail, high winds and lightning, and after the storms abated that night, hoped that they had found shelter and could sleep.
"But where and how do hawks sleep?" I asked John Bateman, and here is his fascinating reply:
"Good question. Where do hawks sleep? It’s a question every hawk watcher eventually asks. The answer is not so evident. Red-tails can be rather circumspect about the matter. They can seem to just evaporate towards dusk.
"But where and how do hawks sleep?" I asked John Bateman, and here is his fascinating reply:
"Good question. Where do hawks sleep? It’s a question every hawk watcher eventually asks. The answer is not so evident. Red-tails can be rather circumspect about the matter. They can seem to just evaporate towards dusk.
In fact, they can sleep in several kinds of perches. Out here in the Ohio countryside, on an evening when the hawks perceive that the night will be calm and rather windless, old haggards (adults) will commonly park themselves on the tops of tall utility poles and sleep the night out on this otherwise exposed perch. I have seen birds take such a perch at dusk, and saw them there the next morning at dawn.
But for years, the missing nights were a mystery. Where do the hawks sleep on windy, rainy nights, the ones where we’d like to be snuggled tightly under the covers, perhaps with our husband or wife? The answer has appeared recently by the diligent hawk watchers in Central Park following the exploits of Pale Male, the great red-tail that began the species’ urban incursion back in the 1990s. People in New York followed the bird closely, and were able to see him fly into trees and assume a night time, sleeping perch.
When they sleep, they turn their heads around and tuck them into the fluffed-up feathers of the back. I’ve quietly watched my sleeping falconry hawk with a dim flashlight. A sleeping hawk looks morbidly headless. I once had a wonderful red-tail that I took on my public lectures. She was so tame that on the way home at night she would sit on a perch I placed on the passenger seat of my car. Like a little child, the hawk would be fast asleep after driving just a mile or two at night. I’d look over there, and there she was–utterly without a head. It didn’t bother me. But when I stopped at a stop light and some trucker looked down into my car, the presentation was a bit eerie. I merely waved and moved on. That bird caused a lot of late night scratched heads.
It’s now pretty obvious that on rainy, windy, or otherwise unfavorable nights red-tails typically fly into a large hardwood tree, perch on a horizontal limb that allows the toes to wrap around the branch and grip it. But on a cold, windy, rainy, winter’s night, it would seem hard to be able to sleep in such a position. Here’s how it’s done.
Red-tails, like most other birds, have an interesting and useful foot locking mechanism used when sleeping. As the bird begins to nod off, there is a ratchet-like band of tissue that can be tightened around the inside of the leg. Once tightened, it sticks together somewhat like velcro, locking the bird’s grip on the branch. The hawk doesn't have to pay any attention to holding on during the night. The bird’s toes are physically locked around the branch, and normal winds cause no problems.
Red-tails, like most other birds, have an interesting and useful foot locking mechanism used when sleeping. As the bird begins to nod off, there is a ratchet-like band of tissue that can be tightened around the inside of the leg. Once tightened, it sticks together somewhat like velcro, locking the bird’s grip on the branch. The hawk doesn't have to pay any attention to holding on during the night. The bird’s toes are physically locked around the branch, and normal winds cause no problems.
I’ve never encountered a sleeping red-tail in a gale. I think in those situations the bird must both lock its toes around the branch, and also stay awake and lean over into the wind. I don't know this, either, but I presume that the birds in these situations will attempt to park themselves in a somewhat protected position in the tree or woodlot. And this is why it would be so good to put a radio transmitter on a wild red-tail and find out just where the bird sleeps each night.
What about heavy rains? This is exactly why red-tails spend so much of their time diligently preening their feathers. As with all birds, they have the oil gland on their rump. The lean over and strop their bill on this gland, pick up some feather oil, and then preen it into all the feathers on the body. When well-preened, water runs off a hawk’s back almost as well as water off a duck’s back. Still, in the heaviest down pour, the outer feathers can get soaked. But the fluffy, inner down feathers remain oiled and water repellent. After a summer rainstorm we often seen a sodden red-tail. Underneath, though, she’s warm and dry. Red-tails, like all birds, are like turtles. They carry their houses of feathers with them wherever they go.
And except for the incubating mother, the parent hawks do not sleep in or on the nest. Hawk watchers should not regard the nest as a “home,” in any human sense. Yes, the birds stay near the nest, and often sleep within a hundred yards or so of it. But it’s not a place Mom and Pop try to go back to in any human manner. It’s important to understand that.
One other thing that was wonderfully discovered with Pale Male in NYC was that when he took his night perch, sometimes at some distance from the nest, he always seemed to maintain a straight, clear visual path to the nest. He could see the nest from where he slept. Even in thick branches there seemed to be always a clear view of the nest.
That, then, raises the question of how well the hawks can see at night. From watching my several falconry red-tails over the years, it seems pretty evident to me that they can see at night just about as well as I can. That’s not too powerful. But I have some evidence that red-tails may be able, like rattlesnakes, see a bit down into the infrared spectrum. If that’s so, a distant red-tail taking an hourly peek at its distant nest and incubating mate at night may be able to easily seen a heat-emitting, thereby infrared-glowing raccoon ascending the nest tree in search of a nighttime hawk egg snack.
For red-tails, this nighttime vision is still a bit sketchy and conjectural. That’s not the case, however, for peregrine falcons, who have remarkable nighttime vision capabilities. But that’s another (too lengthy) story to relate here.
–John Blakeman
Thursday, June 25, 2009
Carditoo's account of the exciting June 25th Philly hawk activity
Carditoo (Carolyn Sutton when not on Twitter) often goes down to the Franklin Institute early in the morning to check out our hawk family. She was there today (Thursday) and sent me this account of all the morning's excitement:
"When I arrived at the Parkway this morning at 5:45 AM, it was depressingly overcast, damp, quiet and deserted. I looked around for 15 minutes and saw no trace of our hawk family. Maybe, I thought, they would not appear on such a dreary morning.
I was thinking about leaving when I heard that familiar hawk call from the trees. BAM - the family was everywhere, at least one parent and three eyasses. I simply could not follow the action.
The racket was incredible; hawks calling back and forth non-stop; other birds twittering excitedly as they took off for less threatening places. The hawks were flying through the trees in hot pursuit of anything they saw. One swooped down low across the front of the Library headed east. The other two zig-zagged through the trees and zoomed north up 20th Street after a flock of starlings.
Then, I watched one eyass fly onto the Civil War monument with its prey, followed immediately by a parent and sib. The sight of an eating eyass that doesn’t want to share is priceless – wings draped over the dead critter like Dracula over his victim.
The interlopers left in pursuit of their own prey, dive bombing across the Parkway and sweeping the grasses around 21st Street. Don’t know about the hawks, but I was breathless and was almost happy that they all disappeared for a while. Actually, that was the last I saw of the parents.
But, very shortly, two eyasses returned and met in the trees directly over my head, the closest I have been to them since Miss Piggy walked across the street in front of me on the day of Rick’s rescue. The third eyass flew from the Barnes Foundation construction site to the Library ledge and went into “protect-mode” over his/her food. The two above me quickly flew over to join the party.
I was simply ecstatic to see them sitting in a row - like hear/see/speak no evil monkeys - on the Library ledge. KAY, KAY, my kingdom for Kay’s camera! I missed her so.
Realizing that there was no room at their sib’s table, two of the eyasses again took off up 20th Street in hot pursuit of some birds. The last eyass perched for a bit after finishing his meal, then took off, I guess, to rejoin the hunt.
45 minutes of non-stop action, then nothing -- all quiet on the Parkway once more.
"When I arrived at the Parkway this morning at 5:45 AM, it was depressingly overcast, damp, quiet and deserted. I looked around for 15 minutes and saw no trace of our hawk family. Maybe, I thought, they would not appear on such a dreary morning.
I was thinking about leaving when I heard that familiar hawk call from the trees. BAM - the family was everywhere, at least one parent and three eyasses. I simply could not follow the action.
The racket was incredible; hawks calling back and forth non-stop; other birds twittering excitedly as they took off for less threatening places. The hawks were flying through the trees in hot pursuit of anything they saw. One swooped down low across the front of the Library headed east. The other two zig-zagged through the trees and zoomed north up 20th Street after a flock of starlings.
Then, I watched one eyass fly onto the Civil War monument with its prey, followed immediately by a parent and sib. The sight of an eating eyass that doesn’t want to share is priceless – wings draped over the dead critter like Dracula over his victim.
The interlopers left in pursuit of their own prey, dive bombing across the Parkway and sweeping the grasses around 21st Street. Don’t know about the hawks, but I was breathless and was almost happy that they all disappeared for a while. Actually, that was the last I saw of the parents.
But, very shortly, two eyasses returned and met in the trees directly over my head, the closest I have been to them since Miss Piggy walked across the street in front of me on the day of Rick’s rescue. The third eyass flew from the Barnes Foundation construction site to the Library ledge and went into “protect-mode” over his/her food. The two above me quickly flew over to join the party.
I was simply ecstatic to see them sitting in a row - like hear/see/speak no evil monkeys - on the Library ledge. KAY, KAY, my kingdom for Kay’s camera! I missed her so.
Realizing that there was no room at their sib’s table, two of the eyasses again took off up 20th Street in hot pursuit of some birds. The last eyass perched for a bit after finishing his meal, then took off, I guess, to rejoin the hunt.
45 minutes of non-stop action, then nothing -- all quiet on the Parkway once more.
Wednesday, June 24, 2009
John Blakeman answers some more of our questions
Several of you have sent me really interesting questions about hawks in general, and "our" hawks in particular. I forwarded these to John Blakeman, our source of so much expert knowledge. John is a raptor biologist, a Master Falconer, and lives in Ohio.
Do red-tails have predators, other than man?
No, essentially none. By and large, they are the largest, strongest birds in the skies over their territories. They can fend off any other bird that might wish attempt (tragically) to confront them. They are the masters of all they see.
In the West, golden eagles can kill red-tails, but seldom do. Here in the East, bald eagles and red-tails often nest in close proximity, in complete disregard of each other. In my area of northern Ohio, near Sandusky, a bald eagle occupied an existing red-tail’s nest. The eagle added more sticks, bringing it up to eagle size. But the red-tails just went 200 yards to the other end of the woodlot and quickly built a new nest and raised eyasses there.
The one bird of concern is the great horned owl, a true monster of the night sky. These powerful raiders of the darkness can kill anything less than 10 lbs., including a sitting red-tail formel on her eggs. But natural selection has brought about a rather remarkable detente, a genetically understood state of affairs between these two avian predators.
A great horned owl could easily kill a sleeping red-tail, but this virtually never happens, for an interesting reason. In the distant past, when the big owls killed off the local red-tails, they then found themselves without any nests. As it happens, great horned owls, thieves that they are, are unable to actually build a nest. They don’t have the instinct to pluck off sticks and arrange them into a functioning nest. The attribution of wisdom is misplaced with owls. They are totally dependant upon other species or conditions for their nests. That’s why great horned owls start nesting as early as December, allowing them to confiscate a red-tail’s nest before it’s used by the hawks.
Great horned owls that killed red-tails were subsequently unable to find a good nest to use. They therefore died out. So, these owls no longer kill or harass red-tailed hawks. They still, from time to time, steal nests in the winter, requiring the hawks to build a new one. But this works out really well, as red-tails are very good nest builders (well, except for first-time nesters, where the nests often fall apart – but that’s another story).
And is man a predator of red-tailed hawks?
Not any more, to any noticeable degree. That’s exactly why these hawks have come into central Philadelphia. Until recently, red-tails were trapped, shot, or poisoned by certain groups. By a few, they were thought to consume desirable game animals and chickens - vermin, to the hawks.
But that’s no longer the case. Very, very few hawks today are shot, trapped, or poisoned. The countryside is now saturated with adult red-tails. There are no longer any unoccupied red-tail habitats out of town. Consequently, young red-tails, including those from this nest this year, will have a difficult time finding a place to nest and raise their own families.
If our eyasses head out of town to breed in two or three years, they will find the countryside loaded with resident red-tails. The only unoccupied habitats are those left in cities. Pale Male, the world-famous red-tail in Central Park in New York, began this urban incursion almost 20 years ago. Red-tails are coming into cities and learning how to live there across North America. But none of these urban residents have been so accommodating as the Franklin Institute family.
If our eyasses head out of town to breed in two or three years, they will find the countryside loaded with resident red-tails. The only unoccupied habitats are those left in cities. Pale Male, the world-famous red-tail in Central Park in New York, began this urban incursion almost 20 years ago. Red-tails are coming into cities and learning how to live there across North America. But none of these urban residents have been so accommodating as the Franklin Institute family.
Because of their success, there is the greatest chance that the two haggards will resume breeding and nesting once again next year at the FI.
Friday, June 19, 2009
EYASS DIARY - THURSDAY, JUNE 18
So on Thursday, June 18, we got brave and decided to move buildings from the Franklin Institute to the Free Library across the Benjamin Franklin Parkway.
There's this cool tree that's flat and springy, and you can jump up and down on it like it's a trampoline.
Here I am showing off to Portico my bouncing skills. The Eyass Growth and Development Manual says we should be beyond bouncing now that we know how to fly, but it's SO MUCH FUN!
The Library has lots of great perching spots for us to practice our patience and observation skills. The Eyass Growth and Development Manual says, "Eyasses need to learn to perch patiently on high elevations in order to observe potential prey." So I here I am perching confidently and observing carefully. Hawkeye - that's me!
Mom is always swooping around checking on us, and it gets quite tiring trying to be on alert and perching confidently and all that. No matter how far away she seems, she can always see what we're up to.
So when I know for sure that Mom is nowhere near, I sit back on my tail, and relax a bit. But I'm keeping my talons clenched and at the ready, just in case there's something to catch down there.
But truth be told, I can't see anything that I'd like to eat - just boring trees and the sidewalk, and that photo lady racing around with her buddies trying to see where we are. Now that we're not on the nest anymore, I guess they want to know where we all are.
That nest was a real drag. All we could do was hop/fly over to the ledge, then fly/hop back. Those hawkaholics thought that was SUCH a big deal, but look at us now! We're flying all around the Franklin Institute, the Free Library and the Ben Franklin Parkway. We're BIG SHOTS! I love flying around and landing on all these cool buildings. This flying thing is a breeze. Just take off....glide a bit, then land. I can do that all day. I LOVE flying.
Right beside the Parkway is this great avenue of trees, like a hawk runway. I love flying right down the middle. It's a great place to practice tree landings. The Eyass Growth and Development Manual states, "Eyasses need to learn to fly confidently and land on different terrains such as ledges, tree branches, dead trees, and lamp-poles." I like the flying part much better than the landings. So I decided I'd better practice them a bit, and chose the top of a fancy lamp-post for my practice site.
Here I am coming in for a landing. Not sure this was such a great choice for practicing - I can't see anywhere to get a grip. Maybe that top edge....
Yikes - this is harder than I thought, and the spike is sticking in my wing. This was NOT a good idea.
I'm outta here! Not a bad take-off, all things considered. I'm heading over to a dead-looking tree beside the Library. Dead trees are easier, because you can see where the branches are.
OK - wheels down, flaps up,
coming in to land....
looking good
PERFECTO! Damn, I'm GOOD!
No problemo - piece of cake!
I made that look sooo easy.
Mom, mom - did you see that?
Mom, were you watching, mom?
We have to learn this stuff so we can catch our own food. But catching something to eat is really hard. And Dad just sits there watching. He thinks he is such a cool dude sitting on that spotlight all afternoon. I bet I could land on that just fine if he would ever move.
Uh oh, I think he heard that. How did he know I was here? He must have eyes in the back of his head!
Well, you don't look so cool now, Mr. Big Shot, sitting on your spotlight for two hours in the rain. Get a life!
OK - back to the Manual. It says, "Young eyasses must master the flying skills to land safely on a pre-selected tree branch, and then develop the flying skills to land on a prey creature such as a sparrow or pigeon."
JUST as I read that, I saw a pigeon sitting in the tree next to me. I flew over and just landed on it and grabbed it. It never saw me coming. Yay - I caught something!
Then I flew over to the pine tree by the Free Library that was flat-topped - like a table. I landed there with the pigeon I just caught - not an easy feat when you're trying to hold onto the pigeon and grab a branch. Here I am looking around to make sure everyone saw what I just did!
And then Mom suddenly appeared out of nowhere, landed right beside me, and started plucking MY pigeon. I guess she thought I needed help, or something. And THEN, she had the nerve to eat some of it. Sheesh, not only are we losing our 24 hour food service, but we have to SHARE?
The other two, not as accomplished as I, sat on their branches watching me enviously. Go catch your own pigeons, I say!
And when I was done eating, I flew nonchalantly up to the balustrade along the edge of the Library's roof, cleaned off my beak and talons, and rearranged my wet feathers.
The camera lady was running around in the rain snapping away as all this was happening. I guess we're getting quite famous! Maybe they'll put us on a T-shirt.....
There's this cool tree that's flat and springy, and you can jump up and down on it like it's a trampoline.
Here I am showing off to Portico my bouncing skills. The Eyass Growth and Development Manual says we should be beyond bouncing now that we know how to fly, but it's SO MUCH FUN!
The Library has lots of great perching spots for us to practice our patience and observation skills. The Eyass Growth and Development Manual says, "Eyasses need to learn to perch patiently on high elevations in order to observe potential prey." So I here I am perching confidently and observing carefully. Hawkeye - that's me!
Mom is always swooping around checking on us, and it gets quite tiring trying to be on alert and perching confidently and all that. No matter how far away she seems, she can always see what we're up to.
So when I know for sure that Mom is nowhere near, I sit back on my tail, and relax a bit. But I'm keeping my talons clenched and at the ready, just in case there's something to catch down there.
But truth be told, I can't see anything that I'd like to eat - just boring trees and the sidewalk, and that photo lady racing around with her buddies trying to see where we are. Now that we're not on the nest anymore, I guess they want to know where we all are.
That nest was a real drag. All we could do was hop/fly over to the ledge, then fly/hop back. Those hawkaholics thought that was SUCH a big deal, but look at us now! We're flying all around the Franklin Institute, the Free Library and the Ben Franklin Parkway. We're BIG SHOTS! I love flying around and landing on all these cool buildings. This flying thing is a breeze. Just take off....glide a bit, then land. I can do that all day. I LOVE flying.
Right beside the Parkway is this great avenue of trees, like a hawk runway. I love flying right down the middle. It's a great place to practice tree landings. The Eyass Growth and Development Manual states, "Eyasses need to learn to fly confidently and land on different terrains such as ledges, tree branches, dead trees, and lamp-poles." I like the flying part much better than the landings. So I decided I'd better practice them a bit, and chose the top of a fancy lamp-post for my practice site.
Here I am coming in for a landing. Not sure this was such a great choice for practicing - I can't see anywhere to get a grip. Maybe that top edge....
Yikes - this is harder than I thought, and the spike is sticking in my wing. This was NOT a good idea.
I'm outta here! Not a bad take-off, all things considered. I'm heading over to a dead-looking tree beside the Library. Dead trees are easier, because you can see where the branches are.
OK - wheels down, flaps up,
coming in to land....
looking good
PERFECTO! Damn, I'm GOOD!
No problemo - piece of cake!
I made that look sooo easy.
Mom, mom - did you see that?
Mom, were you watching, mom?
We have to learn this stuff so we can catch our own food. But catching something to eat is really hard. And Dad just sits there watching. He thinks he is such a cool dude sitting on that spotlight all afternoon. I bet I could land on that just fine if he would ever move.
Uh oh, I think he heard that. How did he know I was here? He must have eyes in the back of his head!
Well, you don't look so cool now, Mr. Big Shot, sitting on your spotlight for two hours in the rain. Get a life!
OK - back to the Manual. It says, "Young eyasses must master the flying skills to land safely on a pre-selected tree branch, and then develop the flying skills to land on a prey creature such as a sparrow or pigeon."
JUST as I read that, I saw a pigeon sitting in the tree next to me. I flew over and just landed on it and grabbed it. It never saw me coming. Yay - I caught something!
Then I flew over to the pine tree by the Free Library that was flat-topped - like a table. I landed there with the pigeon I just caught - not an easy feat when you're trying to hold onto the pigeon and grab a branch. Here I am looking around to make sure everyone saw what I just did!
And then Mom suddenly appeared out of nowhere, landed right beside me, and started plucking MY pigeon. I guess she thought I needed help, or something. And THEN, she had the nerve to eat some of it. Sheesh, not only are we losing our 24 hour food service, but we have to SHARE?
The other two, not as accomplished as I, sat on their branches watching me enviously. Go catch your own pigeons, I say!
And when I was done eating, I flew nonchalantly up to the balustrade along the edge of the Library's roof, cleaned off my beak and talons, and rearranged my wet feathers.
The camera lady was running around in the rain snapping away as all this was happening. I guess we're getting quite famous! Maybe they'll put us on a T-shirt.....
Wednesday, June 17, 2009
What could still go wrong for this hawk family?
Good news so far for the Franklin Institute hawk family as they make the transition away from the nest. All three eyasses are flying strongly and confidently, the parents make food runs for them, and we hawk watchers have a bigger territory to observe than that window ledge on Winter Street!
I asked our Ohio raptor expert, John Blakeman, whether it is a strain on the haggards (adult hawks) to have three eyasses to tend/feed/watch out for rather than the more usual two.
John's reply:
"No, not at all, for this reason. The number of eggs a formel lays is directly related to the amount of food she's able to capture and eat in mid-winter. If finding prey is difficult, she will lay only one or two eggs. Red-tails that hatch three eyasses have an ample amount of food they can capture and consume.
The parent haggards of this nest are ample providers. I never once saw the eyasses go hungry. Life for these parents is really good - lots of rats, mice and pigeons to easily capture; a good, solid nest (thank you, Franklin Institute); and now three eyasses successfully fledging and growing up. Life could not be better for any red-tailed hawks anywhere. Philadelphia, city of brotherly love. Philadelphia, city of hawk success. These are happy, contented hawks. Nothing could be better for them."
I then asked John what could could still go wrong for this hawk family.
John replied, "In honesty, because they are wild animals, just a lot of things could go wrong. It’s tough out there, and only a small fraction of hawks that fledge ever survive to adulthood, in two or three years.
All three of this year’s eyasses may perish before becoming adults. They can be hit by a car, even on the Parkway, as a bird shoots across the road closing in on a mouse in the grass. Young red-tails sometimes crash into wires, fences, or poles and break a wing, or otherwise become disabled. Lastly, they could become infected with several lethal diseases, including aspergillosis - a fungus in the lungs (sadly, my eight year old falconry red-tail died of this last winter), frounce - a protozoan infection of the mouth and lungs, or just plain starvation.
I asked our Ohio raptor expert, John Blakeman, whether it is a strain on the haggards (adult hawks) to have three eyasses to tend/feed/watch out for rather than the more usual two.
John's reply:
"No, not at all, for this reason. The number of eggs a formel lays is directly related to the amount of food she's able to capture and eat in mid-winter. If finding prey is difficult, she will lay only one or two eggs. Red-tails that hatch three eyasses have an ample amount of food they can capture and consume.
The parent haggards of this nest are ample providers. I never once saw the eyasses go hungry. Life for these parents is really good - lots of rats, mice and pigeons to easily capture; a good, solid nest (thank you, Franklin Institute); and now three eyasses successfully fledging and growing up. Life could not be better for any red-tailed hawks anywhere. Philadelphia, city of brotherly love. Philadelphia, city of hawk success. These are happy, contented hawks. Nothing could be better for them."
I then asked John what could could still go wrong for this hawk family.
John replied, "In honesty, because they are wild animals, just a lot of things could go wrong. It’s tough out there, and only a small fraction of hawks that fledge ever survive to adulthood, in two or three years.
All three of this year’s eyasses may perish before becoming adults. They can be hit by a car, even on the Parkway, as a bird shoots across the road closing in on a mouse in the grass. Young red-tails sometimes crash into wires, fences, or poles and break a wing, or otherwise become disabled. Lastly, they could become infected with several lethal diseases, including aspergillosis - a fungus in the lungs (sadly, my eight year old falconry red-tail died of this last winter), frounce - a protozoan infection of the mouth and lungs, or just plain starvation.
At least for a few more weeks, probably until mid-summer, the parents will provide food. But when the days begin to markedly shorten in late summer and fall, the parents close the pantry door. The eyasses must by then have learned to hunt and kill on their own. A few birds fail in these endeavors and starve to death. Again, as wonderfully nice as all of what we saw seemed to be, each of these birds, especially the eyasses, are always close to a rapid or unforeseen demise. No animal in nature lives with any special security. Injury, disease, and death are always near at hand.
I mention all of this so that if anything untoward might happen, it could be understood as a part of the larger natural scheme of things. Have any of us pondered the pain that was suffered by the rats, mice, and pigeons that our birds so brutally killed? From a mother mouse’s perspective, to be inappropriately anthropomorphic, our hawks are brutal and uncaring killers."
- John Blakeman
- John Blakeman
Monday, June 15, 2009
Are our hawks doing OK?
Now that our hawks have left the nest it is much harder to know how they are doing. Those of us fortunate to be able to observe down on the Parkway and around the Franklin Institute have had many sightings of the hawks engaged indifferent behaviors. John Blakeman, our raptor biologist from Ohio, provides this commentary on what have been seeing over the last couple of weeks.
John Blakeman writes:
"What you are now seeing with the fledged eyasses over in the trees and on the roof is, like all of the previous marvels of this hawk family, rather typical (and yes, marvelous) stuff.
As you noted, the eyasses are starting to get the fly-through-the-air thing down. This they pick up in just a day or two. No problems out there in the bare air. A slight miscalculation in yaw, pitch, or roll up there in the sky yields no insurmountable difficulty.
But landing, especially on a tree branch amongst a bunch of others, does. You have noted how awkward the eyass's landings have been. This will continue to some degree until July, when they'll have it all figured out.
And you noted the awkward difficulty one of the eyasses had in a tree trying to pull apart a rat that a parent had provided. That's a tough thing to do, to be able to first remain upright and balanced on that thin branch, while at the same time trying to balance the dead rat also on the branch, while at the same time trying to reach down and pull the rat apart. Yep, it fell out of the eyass's talons -- probably just before the eyass herself would have fallen off the branch.
Learning how to coordinate all of these various balance points doesn't come naturally. In a few weeks, the eyasses will have learned how to take off, land, and hold on to prey species while ripping them apart into tidbit-sized pieces. But for a while, watching all of this can be like watching a toddler trying to stuff a spoonful of breakfast into his mouth. For baby humans, they just have to sit there and try to get the spoon in the right place. For the hawk, she's got to keep her balance on the limb, hold on to the prey, powerfully rip open the prey with her beak and strong back and neck muscles, and then swallow the ripped-off piece of rat flesh. To do that easily and consistently requires some practice. That's what the parents are watching their eyasses learn how to do right now.
And all of the hawk watchers there in Philadelphia get to see this, too. Out here in rural areas, the hawks stay away from nearby humans, who so seldom get to see so closely these hawk behaviors.
For a good time, as you mentioned, not a single hawk, eyass or haggard, was to be seen. Then, out of nowhere they started to appear. Welcome to red-tailed hawk watching. The birds were very much in the area, probably not a quarter mile away, mostly just a block or two. But they were probably perched in a hunting mode, looking for lunch. As soon as somebody found lunch, a rat perhaps, everyone else saw that and the family came together within a few hundred yards of the nest. This will happen time and again. It's the way of red-tail families in early summer.
One other thing that all of the hawk watchers in Philadelphia should be aware of, and it's something I tried to impress upon the legion of hawk watchers in Central Park in New York City. Please take special pride in your abilities to watch the The Franklin Institutes's red-tail family. It's unlike anything we are allowed to see out here in more typical, rural red-tail habitats. Out here, our red-tails have a decided natural fear, even a repulsion, of humans.
As a raptor biologist I have to go to great lengths to obscure my presence anywhere near a red-tail's nest if I want to see anything like you got to see at the Franklin Institute. If I were to walk within two football fields of a nest up in an Ohio woodlot, the sitting formel will either hunker down, or simply fly off the nest. I get to see nothing so intimately on the nest as we all did with the Institute nestcam.
As a raptor biologist I have to go to great lengths to obscure my presence anywhere near a red-tail's nest if I want to see anything like you got to see at the Franklin Institute. If I were to walk within two football fields of a nest up in an Ohio woodlot, the sitting formel will either hunker down, or simply fly off the nest. I get to see nothing so intimately on the nest as we all did with the Institute nestcam.
Now along the Parkway, you will be able to see the birds flying over the trees, sitting in them, and acting quite naturally, in utter disregard of the humans below. Please take delightful and appreciative advantage of this. Out here in typical rural red-tail habitats, we never are able to see the birds so closely. You've got it better than you know!
My best.
--John Blakeman
Saturday, June 13, 2009
DIARY OF AN EYASS (young hawk)
On the hot, humid, hazy Friday afternoon of June 12, three hours of hawk watching eventually yielded sightings of two eyasses and one parent. Kay captured the action, such as it was.
For the anthropomorphically inclined, this is possibly what was going through the mind of one of those eyasses.
Well, here I am on top of the Franklin Institute. In my copy of the Eyass Growth and Development Manual it states, "When hungry, sit on top of the tallest building, and await parent food delivery."
Well, I'm definitely hungry, so here I am.
What a view, and I've got it all to myself! I wonder where the others are - probably wimping out in a tree staying cool, though I have to admit that the last time I flew into a tree it wasn't pretty. It's hard to pick which branch to land on before you crash into it, so I'm sticking with roof landings for now.
It's really high up here. I wish I weren't by myself. Maybe they're all back on the nest having lunch. I'm going to lean over the edge and see what's happening down there. Yikes....it's a long way down. I can see those silly hawk watchers.
"GET A LIFE, GIRLS!"
I think they must have shifts or something, because when one crew leaves, another shows up within ten minutes.
It's pretty boring being an eyass once you leave the nest. Most of the time you're sitting up on a roof, or lamp post or
monument waiting to be fed. We're supposed to be practicing our flying skills so that we can catch our own food, but I can't see that happening for a while. Better practice some wing flapping while I'm waiting. Maybe mom will see me up here if I'm jumping around a bit.
It's sooo BORING up here. I'm tired of looking at the view and this stupid roof. I'm going to hop down behind that balustrade thing and see what's happening down there.
This is very cool! I can peek out but no-one can see me. The hawk watcher gals go nuts when we suddenly disappear! That camera lady keeps firing away even though these pillar things will surely mess up her picture.
Oooh, but wait.... if no-one can see me, then I won't get fed. Gotta get out of here fast, and back where mom can spot me for a rat drop-off.
Uh oh...here she comes, and I'm not on the roof where I'm supposed to be.
"MOM!"
Can she see me down here?
"MOM! Wait!!! WAIT....don't go.....I'm down HERE....WAIT!!!"
Oh, she's gone. She couldn't see me. But, you know what? She didn't have any food anyway. She was just checking up on me. Gotta get back up top and start flapping if I'm ever going to get fed.
OK - I'm right on the edge. I'm going to start easy. Wow, the wind is quite strong. Let's not have a repeat of what happened Saturday when I flew off the nest by mistake, couldn't fly back up and had to be rescued. That was sooooo embarrassing.
Now I'm gettin' into my groove here. I am just SO good at flapping! I swear my wings are getting longer by the minute. Hey, think I could audition for that thing on the hood of Rolls-Royces?
Flap, flap, flap......Whee, I'm almost flying! I LOVE this! Look at me, everyone!
How does that song go.....
"....so high against the sky, so high I almost touch the sky.
Thank you, thank you, thank God for you,
the wind beneath my wings."
I can't flap ANY more. I'm tired. Where are they? They're supposed to feed us every couple of hours. I can hardly remember my last meal. I am SO hungry.
Whoa...what's that? Is that a bird? A plane? MOM??
Guess I'm just going to have to sit up here and wait some more. Our Eyass Growth and Development Manual says, "In order to become an effective hunter, the young eyass has to learn to sit patiently for long periods of time."
I'd better be gettin' an A on that section.
Friday, June 12, 2009
Have feathers, will fly
Here's some more knowledgeable commentary from John Blakeman on how young hawks develop their flying skills, and why Miss Piggy had some difficulty on her first foray from the nest. John commends Rick Schubert for his expert handling of Miss P. during her capture and release.
"Some comments on the early, weak flight of the retrieved hawk [Miss Piggy]. It’s been proposed that the bird’s flight feathers were not yet long enough, or mature enough, to allow full flight, thereby causing the bird to end up weakly on the ground. The bird did have a weak landing, and it couldn't fly very well, but it didn't leave the nest too soon.
"Some comments on the early, weak flight of the retrieved hawk [Miss Piggy]. It’s been proposed that the bird’s flight feathers were not yet long enough, or mature enough, to allow full flight, thereby causing the bird to end up weakly on the ground. The bird did have a weak landing, and it couldn't fly very well, but it didn't leave the nest too soon.
What happened with this bird is very common with rural red-tails. On the nest, the newly-feathered eyasses get antsy about flying somewhere. First, it’s just some jumping up and down with awkward wing flaps, as we saw with these birds two weeks ago. Then, the eyasses start to do short jumping flights from one side of the nest to the other, just as we saw. Next, where possible, they try to “fly” from the edge of the nest a few inches to a new branch. This nest, like many on rock ledges in the West, had no branches (not in a tree), but the window ledge worked as a landing pad for the short flights.
Finally, the birds just jump off and see how this flying thing works. And just like a little toddler tries to learn how the walking thing works, the newly-fledged (well, partially-fledged) eyass finds that flying is both wonderful and exhausting. Most of the eyasses try to quickly find a nearby tree limb to land on. But the poor little things have never been suspended out in the open air, and trying to control their flight requires neuromuscular coordination and reflexes that are yet undeveloped.
In the best of situations, the eyass is able to glide clumsily into a tree and crash land onto some branches. Often, on the first flight, the bird grabs a limb but falls over, hanging upside down. It then either tries to power itself upright onto the branch, or it finally just lets go and falls in a loose clump to the ground. There, it gathers its breath and later tries to take off and achieve a more artful landing.
That was the situation with the retrieved bird [from last Saturday]. It was all very natural, something that most red-tail eyasses have to endure in their first flights. In the rural wild, all of this happens at the edge of a woodlot or in an open meadow environment. The bird may stay grounded for a day or two, and the parents bring food to it as it clambers up into a low bush or short tree. Soon, however, the young bird figures out how to take off and land, and becomes an accomplished creature of the sky for the rest of its life.
The feathers of this bird were not too short. But as the wonderful photo showed, they had not completely emerged from the feather sheaths. That’s what the eyasses were attending to for much of each day in the last weeks. Everyone noticed (thanks to the wonderful camera) how much time the birds spent “preening,” tucking their heads down into their feathers. In fact, they were using their bills to strip off the drying feather sheaths, allowing the growing feathers beneath to emerge. For the large flight feathers, the feather sheaths still remained at the base and shank of the larger feathers, as seen in the photo.
It’s not that the flight feathers weren't long enough. They are now full-sized. But they are still, as we say, “in the blood.” As the feathers grow out, they actually have blood vessels within, nourishing the growth of these miraculous body features. So, for a while, heavy blood remains coursing through the big tail and wing feathers. Until this ends, when the bird is “hard penned,” the wings are a bit heavier. Right now, all three birds should be close to being hard penned, allowing for much better flight.
Everything that happened with the fledging of The Franklin Institute eyasses was absolutely normal for red-tailed hawks. And I commend the Institute for all that was done to let the public experience this wonderful story.
I commend Rick Schubert for his expert handling of every aspect of the capture and release of the bird.
I commend Rick Schubert for his expert handling of every aspect of the capture and release of the bird.
Frankly, just everything about this entire event has worked so wonderfully. My very best to everyone in Philadelphia. Everyone there should be so proud of this exemplary red-tailed hawk family, which became so personally a part of our own."
--John Blakeman
Thursday, June 11, 2009
The joys of downtown hawk watching
Yesterday afternoon, I was reminded again how remarkable an experience it is to watch this pair of red tail hawks raising their family amid the skyscrapers and expressways of downtown Philadelphia.
I spent a couple of hours on the street outside the Franklin Institute observing the nest and the surrounding buildings and trees hoping to see the eyasses and their parents.
I was joined by Kay Meng who took the remarkable images you see here, and several other hawkaholics. It was a humid, hazy afternoon, and for the first hour we saw nothing but an empty nest and empty sky. We entertained ourselves and our Twittering followers by parading on the sidewalk where the hawkcam inside the Franklin could pick us up, and then watching this idiocy on my laptop - hawkwatchers watching hawkwatchers watching hawkwatchers!
Suddenly, from nowhere a parent hawk flew past the empty nest with a large mouse in its talons, and settled on a ledge near the top of the Franklin's roof. A few moments later, an eyass flew in from the trees lining the Benjamin Franklin Parkway, and tried to land near its parent.
It misjudged the ledge and had to cling onto the moulding. It then tried to literally climb up the wall, couldn't get a grip, and had to drop into a tree on Winter Street down below.
The mouse-carrying parent then flew from the roof down to the street, paused almost as if wanting the youngster to see where it was, then flew up into a nearby tree and started calling to the eyass to join it. The eyass flew over and made a wobbly, but much better landing near its parent and was promptly rewarded with the mouse.
Then came the big test - balancing on the branch while holding the mouse with one foot, and then trying to eat it!
While all this was happening, one of the hawkwatchers noticed the other parent sitting on a lamp post, then saw an eyass on top of a nearby monument. This was really exciting as we had four of our five hawks in sight!
The fun began when these hawks started moving. The parent with the mouse left it with the tree eyass and flew up the Parkway, chased furiously by a flock of small birds which it totally ignored. The monument eyass flew into a nearby tree, and we suddenly saw that it was joining the third sibling which had been perching there unnoticed. In all this excitement, we did not see the lamp post parent leave. The mouse eyass finished her mouse and flew strongly out of tree, across Parkway and into another tree. So we had three eyasses in trees, but no parents.
There was a pause in the action, and we looked in awe at the astonishing images that Kay had captured. Every so often, someone would swing their binoculars over to the trees to check on the eyasses, but not much was happening.
Then in the space of about ten minutes we had more hawk action than we could keep up with. I was Twittering away on my laptop as my binoculared compadres were calling out:
"Parent just landed in nest and flown back to tree to feed squawking eyass."
" I've got dad or mom - hard to know. It's sitting on the lamp post."
"Incoming hawks! One on top of the pediment over Fels entrance, and one in tree on Winter Street."
" I've got a parent on top of the FI. I can see a red tail."
" OK - we've got one in the nest, one in the tree and one on the FI."
"The FI parent just took off across the Ben Franklin Parkway towards trees by the Free Library."
" The eyass is still in tree. Dad landed on a window ledge three windows to left of nest."
And so it continued with the birds zipping from one spot to another, while we played Where's Waldo with hawks! And then the magical moment when we knew for sure that this precious hawk family was fully intact:
"OK - we've got an eyass on the monument, one in the tree, mom's flying over there, and dad and one eyass are on the roof - we've got all five!"
So our hawk family is doing just beautifully, thriving in their downtown landscape, while we have the privilege to watch them continue to raise and teach their youngsters the ways of urban hawkdom.
I spent a couple of hours on the street outside the Franklin Institute observing the nest and the surrounding buildings and trees hoping to see the eyasses and their parents.
I was joined by Kay Meng who took the remarkable images you see here, and several other hawkaholics. It was a humid, hazy afternoon, and for the first hour we saw nothing but an empty nest and empty sky. We entertained ourselves and our Twittering followers by parading on the sidewalk where the hawkcam inside the Franklin could pick us up, and then watching this idiocy on my laptop - hawkwatchers watching hawkwatchers watching hawkwatchers!
Suddenly, from nowhere a parent hawk flew past the empty nest with a large mouse in its talons, and settled on a ledge near the top of the Franklin's roof. A few moments later, an eyass flew in from the trees lining the Benjamin Franklin Parkway, and tried to land near its parent.
It misjudged the ledge and had to cling onto the moulding. It then tried to literally climb up the wall, couldn't get a grip, and had to drop into a tree on Winter Street down below.
The mouse-carrying parent then flew from the roof down to the street, paused almost as if wanting the youngster to see where it was, then flew up into a nearby tree and started calling to the eyass to join it. The eyass flew over and made a wobbly, but much better landing near its parent and was promptly rewarded with the mouse.
Then came the big test - balancing on the branch while holding the mouse with one foot, and then trying to eat it!
While all this was happening, one of the hawkwatchers noticed the other parent sitting on a lamp post, then saw an eyass on top of a nearby monument. This was really exciting as we had four of our five hawks in sight!
The fun began when these hawks started moving. The parent with the mouse left it with the tree eyass and flew up the Parkway, chased furiously by a flock of small birds which it totally ignored. The monument eyass flew into a nearby tree, and we suddenly saw that it was joining the third sibling which had been perching there unnoticed. In all this excitement, we did not see the lamp post parent leave. The mouse eyass finished her mouse and flew strongly out of tree, across Parkway and into another tree. So we had three eyasses in trees, but no parents.
There was a pause in the action, and we looked in awe at the astonishing images that Kay had captured. Every so often, someone would swing their binoculars over to the trees to check on the eyasses, but not much was happening.
Then in the space of about ten minutes we had more hawk action than we could keep up with. I was Twittering away on my laptop as my binoculared compadres were calling out:
"Parent just landed in nest and flown back to tree to feed squawking eyass."
" I've got dad or mom - hard to know. It's sitting on the lamp post."
"Incoming hawks! One on top of the pediment over Fels entrance, and one in tree on Winter Street."
" I've got a parent on top of the FI. I can see a red tail."
" OK - we've got one in the nest, one in the tree and one on the FI."
"The FI parent just took off across the Ben Franklin Parkway towards trees by the Free Library."
" The eyass is still in tree. Dad landed on a window ledge three windows to left of nest."
And so it continued with the birds zipping from one spot to another, while we played Where's Waldo with hawks! And then the magical moment when we knew for sure that this precious hawk family was fully intact:
"OK - we've got an eyass on the monument, one in the tree, mom's flying over there, and dad and one eyass are on the roof - we've got all five!"
So our hawk family is doing just beautifully, thriving in their downtown landscape, while we have the privilege to watch them continue to raise and teach their youngsters the ways of urban hawkdom.
Moving on up - from nest to trees
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