Why do the hawks bring evergreen sprigs to the nest?

The nest has been growing steadily as the hawks bring sticks, leaves and twigs on a daily, even hourly basis. The Ustream live camera feed allows us to watch every detail of the hawks' attentive nest-building. We've been struck by the number of evergreen sprigs and fronds that they are weaving around the edge of the nest.

This afternoon, we also saw some free advertizing for City Paper!

John Blakeman offers some perspective on the significance of the evergreens in the nest:

"Nest watchers have noted that the haggards bring sprigs of evergreens into the nest. Almost all red-tails do this, for really unknown reasons.

The conventional explanation is that these pine or spruce twigs have fragrant volatile chemicals that drive off feather parasites. Indeed, such vapors do emanate from evergreens, and there must be a few bugs at a nest with evergreen sprigs. And yes, red-tails can have small populations of tiny feather lice. But these are seldom seen, and cause no health or feather problems in healthy birds. I have never been able to discover any of these on my falconry red-tails.

So repelling arthropod (bug) parasites is not really a factor.

And in fact, just look at where the haggards place the evergreen sprigs. If they are brought to the nest to drive out feather bugs, they aren’t in the right place. Most of them get placed out on the rim surface, where the birds stand, not where they squat. The aromatic vapors from these can’t effectively penetrate through the feathers to the birds’ skin surfaces, where the feather lice (what few there are) reside.

Frankly, the birds themselves keep the feather bugs in control by their frequent and prolonged preening. Nest watchers will see a lot of this, with a bird just standing there with its head turned around and probing through feathers all over its body.

This does two things. Mostly it distributes oil that the bird strokes off by touching its beak to the oil gland on the rump, beneath the feathers there. Then she strokes her beak through her feathers, getting a microscopic layer of this rain-repelling oil all over her body. Like a duck, water generally runs right off the hawk’s back, because of this oil.

Think of that when our formel will be sitting out there in cold March rains, keeping her two or three (we hope) eggs warm and dry. Periodic preening is crucial for this.

But the evergreen sprigs? They can’t be there to repel bugs. Wrong placement.

I really think they’re just really decoration, making things a bit more pretty (well, chromatically luminous for my academic colleagues) than just the bare sticks. I also think it behaviorally conveys commitment by the birds both to the nest and to each other. I don’t think unpaired red-tails ever carry around or do anything with evergreen sprigs.

For fun, I’ve tossed a few of these into my falconry red-tail’s chamber in March, and she does absolutely nothing with them. She pays no attention. It’s obviously a nesting and perhaps a pair-bond thing.

"Here, I brought you this. It shows I love you, and I like our nesting pad here. Don’t we got it good?"

And yes, my academic colleagues will cringe, as I internally do when I present such anthropomorphisms. No, red-tails don’t converse or even think lubby-dubby thoughts. It would be an error to explain what we are seeing in such thoroughly human or mammalian terms. Biologically, it’s not so clearly parallel.

But on the other hand, there are distinct behavioral parallels, although they are not neurologically exact. Hawk brain structure is very different from ours, and they can’t think too deeply on much of anything. Their behaviors are rather ritualistic, just going through the motions, as it were. Their brains aren’t big enough for much more than this.

But that should not discount all the wonderful behaviors we are privileged to watch. It can’t be denied that this is a committed, reproducing couple, tending diligently to bring a new generation of their offspring successfully into the Philadelphia skies.

Everyone can decide for themselves how these behaviors originate. If some wish to assign entirely human traits to these, so be it. It can be fun, and perhaps some children’s literature could derive from what will be seen. On the other end of the spectrum we are cold-hearted scientists, attempting to explain everything in quantitative metrics, and genetic and bio-chemical mechanisms.

But wait! I’m a scientist. But really, those are NOT the reasons I’m watching all of this. I’m as addicted to watching all of this as everyone else. I’m doing this because it’s just so profoundly exciting and fun, to be able go right in the living room and neighborhood of this bird family. We get to see it live and in person. How exciting, for each and all.

Once again, nothing like it in all the world."

–John Blakeman


As I read John's comments about the evergreens, I remembered Barbra Streisand's hit song of a few years ago entitled "Evergreen," and the final stanza of those lyrics does resonate with the commitment of the Franklin hawks to each other:


Two lives that shine as one
Morning glory and midnight sun
Time we've learned to sail above
Time won't change the meaning of one love
Ageless and ever evergreen

When will the eggs arrive?

"When will the eggs come?" is the question now on all hawkwatchers' minds.

John Blakeman has been watching the haggards' activity on the nest via the Ustream camera feed, and offers us these comments:

"I note that a number of posters are wondering when the eggs will be laid. Who knows? But from what I saw today, it's not likely to be right away, perhaps in a few days or so. (But again, who knows? I'm often fooled by these birds.)

Here's one thing that viewers can watch for. The formel, when the big egg really starts to form and descend down her one fallopian tube (mammals have two of these; birds have one, so that they don't have to fly around with un-used extra weight), the hawk will take on a somewhat stiff and concerned "look." She will not be as active and will just sit there for long periods, looking a bit dazed.

And if I had a fallopian tube with a descending mass commensurately as big as the hawk's egg, I'd be dazed, too.

Then, she'll sit down in the nest and get ready. The laying of the egg can't been seen. It just comes out, without much effort. But she'll get up a bit later, turn around, look at it, and then sit back down. That's probably when we'll see that the first egg has been laid.

But serious incubation won't start yet. That happens when the formel knows she's laid the last one. Then, it's serious incubation time. Keep those eggs warm and rotated. She will now sink lower into the nest, and jostle herself back forth, getting the new eggs tucked right up to her naked brood patch, a bare area under the chest feathers. That will keep them warm.

The fun then begins for all of us. Here's awatchin'."

–John Blakeman

Our hawks were on TV tonight!

This evening, our local ABC news affiliate - Action News 6 - here in Philadelphia ran a story on our hawks. Very cool to see the interior of the Boardroom and the window that looks out onto the nest.

The hawks seemed completely unfazed by the TV cameras, much to the surprise of Matt O'Donnell, the reporter. He might have heard the following exchange between the haggards:

"Look, honey, more cameras!"
"Camera, schamera - seen one, seen 'em all."

Click on this link to view the Action News 6 segment.

Keep your eye on the hawks at the Franklin Institute

The scream of a red-tail hawk

John Blakeman has told us that if the hawks were threatened by the presence of humans around their nest, they might scream. The scream of red-tail hawk is unmistakeable! The red-tail in this clip is eating a quail on the fist of its falconry trainer.

John Blakeman commented on this video clip:

"This is a classic red-tail scream. Unfortunately, the bird looks a bit scruffy, probably an artifact of low-res video and You-tube.

More objectionable to me, however, is the bird's deportment. It thinks something or someone is about to take its food or enter its personal space. It has its hackles up (feathers on the back of its head), in a very threatening manner. To me, this looks to be something of a "marhawk," another of those falconry terms that have come down to us from Middle English or Elizabethan times.

A marhawk is a raptor that has been captured for falconry often as an eyass, and has been poorly "manned," tamed, or accommodated to its otherwise new good life in the falconer's care. A poorly manned hawk, especially when taken as an eyass, or trapped in summer, while it is still otherwise in the care or feeding of its parents, easily becomes defensive, as this bird does.

The hawks belonging to me and my falconry apprentices never, ever scream on the fist. Nor do they ever raise their hackles (feathers on the back of the head) in a display of threat or anger. Our birds are like the haggards being watched at the Franklin Institute, calm and regal, in utter control of themselves.

Still, this YouTube scream is authentic and representative. Red-tails don't have much of a vocabulary, and most people hear only the scream. When uttered from 500 ft above the Franklin Institute, or above one of my rural Ohio woodlots, it's a piercing (but not loud) aural highlight that connotes wildness and nobility. It sends a spike of excitement up my spine every time I hear it, whether on a grainy YouTube segment, or better, when it's heard live from above.

As always with red-tails, nothing like it in all the world."

-- John Blakeman

Does activity in the window bother the hawks?

As we know from watching the live camera feed of the hawks on their window ledge outside the Boardroom of the Franklin Institute, there are times when we can see reflections in the glass of activity in that Boardroom. Some viewers recently expressed concern that the proximity of people and their activity might stress or startle the hawks:

"Does anyone know if the hawk's view inside the Franklin Institute window is blocked? I've been concerned that all the activity in there--people with cell phone cameras and other photo equipment right next to the window will cause them to abandon the nest." "One of the most fundamental lessons that I have learned about bird watching is to be discreet, quiet and respectful...I have to wonder if cell phone flash or people viewing them through the window could become disturbing to these hawks."

Gene Mancini from the Franklin Institute who oversees the welfare of the hawks, responded, "The view into the Boardroom is not blocked. I can tell you from observation that the hawks show absolutely no signs of stress at the goings on in the Boardroom. They spend quite a bit of time watching the people as they convene or move about, and do not balk at someone walking right up to them.... initially we were very cautious, but the hawks clearly were looking in to see if there was any activity. I am not aware of anyone using a flash to take photos. And let me assure you, the Boardroom at the Franklin Institute is visited by the smallest of circles... everyone knows the rules. This is our second season with these birds, and one of the premier hawk experts in the nation says our pair is in spectacular shape."

John Blakeman adds this perspective:

"These are seemingly legitimate concerns, that close-up views behind the window might disrupt normal nesting activities. I, too, last year pondered this.

But the record is very clear. The hawks pay virtually no attention to humans behind the window. And this relates to humans everywhere in the nesting area. After watching dozens of wild, rural red-tail nests, I still marvel at how this pair utterly disregards nearby humans. Just the other day I saw one of the haggards sitting on the edge of the nest, looking around. And right there on the corner below was a person crossing the street, heading right toward immediate nest area.

Had that occurred at wild or rural site (these birds really are "wild," utterly unconfined in any way, originating in the wild somewhere), the hawk would have been instantly off the nest. She would have screamed at the intruder, and leapt into the sky, circling in ever higher rings around the guy. His presence would surely have been disruptive, and the hawk would have responded with alarm.

In this case of the Franklin Institute hawk, the hawk paid no more attention to the pedestrian below than a rural hawk pays to a grazing deer or cow -- no concern whatsoever.

But would this accommodation then extend to gawking humans behind the window (and we all gawk when we get to see these birds so closely -- so lucky we are)? Very clearly the birds do accommodate, and this has occurred in other areas. I have reports from several people around the country, in urban areas, where red-tails have landed on building window perches and looked right into human living spaces with curiosity, not alarm. They sit there at length, watching both the humans inside and the landscapes on the outside. Clearly, the hawks understand that the humans inside are restrained by the window. To them, it seems to appear that the humans are strange animals that can walk around inside cliffside rocks. And they never come out of those rocks, either. The hawks on the nest show no concern whatsoever. They probably think we are really weird, trying to live inside rock cliffs.

Now if someone were to come up to the Franklin Institute window and start banging on it, flapping their arms ("Those humans have such weak wings,") the hawks might start to pay attention, probably with a mere look of incredulity. I would of course recommend, as I'm sure the Institute does, too, that no one press their noses or hands against the window pane.

This contrasts markedly with how the hawks respond when one of us raptor researchers climbs up a tree and tries to peer into a wild rural nest. Very different. The hawks will scream, and when close can actually attack. Usually, they do jump off the nest, but circle closely above, trying to divert us. Rural hawks also just don't accommodate people walking around the ground under their nests, either. But here, we must follow the leads of the resident Franklin Institute pair. They've got it all figured out.

Oh, and what about someone taking some flash photos through the window? Well, the flash has no more effect on the hawks than lightning. I've taken hundreds of close-up flash photos of my falconry and research hawks, always without any reaction or concerns by the birds. They are oblivious to it. It's not a concern at all.

--John Blakeman

Sex, Hawks and Rock & Roll!

Yesterday evening, at 7:53 PM, hawkaholics everywhere were riveted by this post from Weaselm on the Ustream chat line:

"Hey Everyone - Big exciting news! A friend, biking home from work at around 5:30 PM, heard a hawk call, looked up and saw two red-tails on the corner of the FI and they started mating!!"

Immediately, the questions - discreet and otherwise - started flying, and roughly in these categories: how, where, when and how often.

So, as always in times of hawk ignorance, I turned to John Blakeman for his wisdom about the sex lives of hawks.

John writes, "It was pleasing to learn that the haggards were 'mating.' But that's not so, in a proper way. The two haggards -- properly -- mated when they came together, started to defend their territory, and began building a nest last year. They mated last December or January (or before). Mating is the social process where two birds decide to share a territory and cooperate in defending that territory, and then build a nest and attempt to produce offspring. Mating is a long-term social process, similar to 'marriage.'

None of this should be confused with what is properly called copulation, sexual transfer of sperm from the tiercel to the cloaca (genital opening) of the formel. Just as human marriage is seldom confused with human sex, hawk mating should not be confused or confined only to copulation.

Frankly, red-tails copulate frequently, many times a day. Copulation is quick, usually about seven seconds.

And copulation is often (but not always) preceded by a series of stupendous dives by the tiercel from a good height down to the circling formel below. Hawkwatchers at this time of the year should be looking above for the haggards soaring in circles. The first amorous signal is the dangling of legs while soaring. This is profoundly sexual.

Then, the tiercel soars to a good height and folds his wings and plunges at well over 100 mph straight at his aroused formel below. Just as he's about to strike her on his rapid plunge (properly called a 'stoop'), the formel turns her wings sideways and allows the tiercel to shoot through her immediate airspace without hitting her.

After dropping beneath the formel, the tiercel throws out his wings and the large G-forces divert his momentum back into the sky. This giant aerial U-shaped flight is one of the most exciting of any bird, matching the lethal prey-killing stoop of a peregrine falcon.

But red-tail love stoops often happen without anyone taking note. Too often, we look for red-tails on buildings in urban areas, and on trees and poles in rural areas. Of course, that's where they spend their time most of the year. But in January, February, and March, we need also to look up into the sky for them.

After the love stoop, the formel then lands on a tall limb or building edge. She leans over in a low horizontal posture, whereupon the tiercel gently lands on her back and grips her between his feet. He wraps his tail back under and around the formel's diverted tail, thereby aligning his cloaca with hers. And in a few seconds, sperm is transferred.

He jumps down off his mate, and both birds often 'rouse,' shaking and rearranging their feathers. Hawks rouse only when they feel good - and after sex, they do, and they commonly rouse.

So, from now on, when the Franklin Institute red-tails are seen to be 'mating,' they aren't. That happened last year, and the birds have been mated since then. But now, in the breeding season, they are copulating many times a day.

For our tiercel and formel, life is good.

Eggs should be forthcoming any time from the second through the third week in March. It could be earlier, or later, but the middle two weeks in March are typical for red-tails at the southern Pennsylvania latitude. In my area, here in northern Ohio near Lake Erie, our birds are about a week later; but they, too, can vary by a week or two.

So, I've suggested the use of three new terms. The birds 'rouse' (pronounced ROUW-ze, rhyming with 'arouse') when they shake their feathers and rearrange them. When they 'mate,' they are really copulating - conducting outright and purely visible and profligate sex. In Philadelphia, no less.

And when the tiercel folds his wings and plunges at great speed toward his formel, or sometimes just when she's sitting, he's performed a stoop, a stunning aerial plunge. Because it's such fun, formels will also tip over and do a stoop, too.

Nothing like it in all the world." -- John A. Blakeman


(Note to self: Think I might like to come back as a hawk....!)

Telling the difference between Mom and Dad

As we watch the increasingly busy activity at the nest, perhaps the most frequent questions are, "Is that Mom?", "Is that Dad?", and "Which is which?"

John Blakeman, our Ohio expert on all things hawk, encouraged us last year to use the correct terminology for the hawks. John is a licensed Master Falconer, a former federal bander of raptors, and also an advisor to Marie Winn and others in New York regarding Pale Male and his nesting exploits there.

John told us, "The male, the father, is the 'tiercel,' pronounced 'TEAR-cel.' He's a bit smaller than his mate. A female hawk is properly called a 'formel.' The parents - the tiercel and the formel - as full adults are properly said to be 'haggards.' In the case of hawks, a haggard is not a scruffy, raggedy old individual. Quite the opposite. A haggard hawk is a full adult, thereby possessing all the knowledge and experiences needed to survive. The 'babies' are neither 'chicks' nor 'babies.' Chicks are little chickens, and these birds are NOT chickens. The proper name for a hatchling hawk is an 'eyass,' pronounced EYE-ess."

So, now that we know how to name them, how do we tell them apart? Kay and I were down at the nest early Saturday and Sundays morning this weekend, and these pictures clearly show the difference in feather color and markings.




The tiercel/dad has a much lighter beak and chin area.









Right under his beak is a white bib that runs into his lovely cream chest, which has just a few scattered spots, almost like a delicate necklace.







The formel/mom, on the other hand, has a much darker bib under her beak - dark chocolate brown in color.





The spots on the formel's chest are more pronounced, almost in lines, and start much higher up.


When you see both birds together, the differences in their coloring are quite obvious. The problem right now is that they rarely turn their faces to the camera, so we don't often see their beak area.














In full flight, the pale coloring and delicate chest speckles of the tiercel are very clear.



Both hawks are now busy bringing materials to line the bowl of the nest. We discovered that some of the pine greenery is coming from a tree
behind the Franklin Institute, when we caught a glimpse of the tiercel caught in the act of pulling off a twig!






The tiercel also flew in with what looked like a pile of leaves from a gutter! Note his cool reflection in the window.



After all the nest activity, both hawks flew off to nearby trees. We saw the formel swoop for a mouse alongside the Vine Street exit ramp.She took her snack atop one of their favorite perching spots - the python-neck lamp posts that are so prevalent in the down-town area of Philadelphia.


The hawks are almost always in sight of their nest at the Franklin Institute. They sited it very effectively when they chose that top floor corner window ledge. In this picture, the hawks' window is the sixth window on the top floor counting to the right from the pillared portico of the Franklin Institute. You can see the tiercel perched on the lamp pole.





Surrounding our hawks are the skyscrapers of downtown Philadelphia. It is magical to watch how beautifully they have adapted to their urban terrain, choosing once more to build their nest here, and hopefully raise their young again, to our great delight!