Thursday, July 21, 2005

Hawks on the Highway: John Blakeman


Another question for John Blakeman, this one from Kentucky, and his answer:


Dear Marie:

John Blakeman writes that adults drive off the first year birds. Why
then does it seem that in my suburban area, the birds I see sitting on
the light poles over the expressway and hunting in the medians are
almost always juveniles, as judged by their by their plumage? Are the
adults too smart to hunt on the expressways, leaving this dangerous
practice for the younger ones, or perhaps all the expressway foragers
are killed so that none survive to be adults? The grassy medians and
shoulders can certainly entice a hungry immature bird but a dive toward
prey can be disastrous if ill-timed with traffic! I would be interested
in Mr. Blakeman's opinion on the expressway hunters.

Thank you!

Sally Seyal, Prospect, KY

Here's the reply. I've emphasized a phrase or two of particular relevance to Central Park:

Sally,
No, both immatures and adults love to hunt from perches along expressways. The grassy margins typically have high populations of voles, the favored food of red-tails.
The simple answer is that the immatures you see along your expressways just happen to be in areas that aren't adult territories. This is particularly true in suburban areas. Central Park notwithstanding, red-tails still prefer to breed in rural or wild areas, not in suburbs or cities. Consequently, immatures who find the voles in your areas are delighted to find spots that resident adults don't claim.
But someone (intelligently) is going to note that they saw both adults and immatures sitting rather closely together, apparently hunting in the same area. I must be careful in stating that adults drive immatures out of their territories. Generally, this is the case. But red-tails being red-tails, there is almost always and exception to very general rule. From time to time an immature will be seen parked right along with a pair of adults in August and September. Why? Probably because the local territory has an exceptionally high concentration of food, so the parents or adults don't perceive the youngster as a competitor for food. (This may be the case in Central Park.)
We know that in late fall and winter, generally after the migration, there can be large concentrations of red-tails of all ages in concentrated, local areas that appear to have large local populations of food. At so-called "game farms," where artificially large populations of captive-reared pheasants are set out for hunters, red-tails of all ages can concentrate in these areas.
As with so much of red-tail biology, availability of food is everything.
If you haven't, try to make mental (or written) notes on the birds you are seeing on your expressways. You will find that red-tails, for periods of anywhere from just a few days, on up to almost months on end, will tend to park at the same locations, at the same time of day. You will begin to note the same birds each day in the same spots, barring abnormal weather.
The blond-headed red-tail that I reported here in Ohio a few weeks ago, a Buckeye Pale Male, was seen sitting on exactly the same fence post at the same time of day for two weeks. He had found a local concentration of voles and exploited it for some time. I looked for him yesterday at the right time and spot, but he was gone. He's changed his daily hunting routine and is perched somewhere else now.
You raised the question of red-tail safety when hunting along major highways. I've never seen an adult killed by a vehicle strike. Adults seem to pretty much understand the rather consistent behavior of motor vehicles. Immatures out on their first hunts in July and August, when powered by the hunger of the season, aren't so competent. They will dive off a hunting perch directly at a distant mouse or vole and pay no attention at all to oncoming traffic. But because their vision includes both narrow-angle telescopic views, along with a wider landscape perspective, most often the immatures will veer away from an approaching car or truck at just the last moment. But not always. Vehicle strikes are a small, but noted hazard to inexperienced immatures.
Hawks must be able to note the position of approaching objects while in flight. The Central Park red-tails, from time to time, must be aware of the location and approach -- often at exceptional speed -- of peregrine falcons. A peregrine dropping out of the sky at 200 mph closes quickly on a red-tail drifting around at 30-40 mph. When dove upon, a red-tail better know how to evade the much quicker peregrine. The same mechanics apply to cars and 18-wheelers humming down a freeway. Fortunately for the red-tail, these wheeled predators generally fly only just above the concrete, seldom in the grass, and never in the sky. By September, most red-tails get it figured out. But I've found a few red-tail roadkills, always in July and August.
In much of North America, particularly outside of the traditional cattle ranges of the West, there just isn't much pasture or meadow available anymore. Voles don't live at all in forests, and have low densities in brush lands. They require open-sky grassy environments, and the thousands of miles of Interstate and expressway rights of way are now prime red-tail habitats, as you've seen in Kentucky. Highways are major survival factors for red-tails and kestrels, who use them for the same reasons.
Sincerely,

John A. Blakeman

Tuesday, July 19, 2005

Oh Brother


<>Thought you'd be interested in a letter I received yesterday, posted with permission:

Marie,

Thank you for sharing your love of the NYC red tails and providing this forum for it. I’m particularly impressed, of course, with the writings of one John Blakeman. Being his brother, you’d think I might have had the opportunity to read his stuff from time to time, but frankly, I haven’t before this. It’s just very good writing. And, it is truly his voice. His passion for RTs mirrors his passion for life, a great privilege enjoyed while growing up.

Thanks again for this forum. Best wishes for your next hawk project.

Regards,

Jim Blakeman

Redtail questions and answers and a word about Pale Male [Sr.]: Blakeman




A website correspondent writes:

Hello Marie,

I found your website, and I thought you might be able to help me out. I have been observing a pair of Redtails for 2 years now. The first year I watched them build their nest and how sad it was that they did not produce any young. I believe Vultures snatched the young. This year however they did produce and on June 16th a baby fledged the nest. I have pictures and movies from beginning to now. Yesterday I took the picture that is I am sending.

Before I ask my question I have to tell you the [redtail] Mother is no longer around, but she was for about 3 weeks, the Father would bring in the food for the baby and would make the baby come to him which I understand would be teaching him. The baby is flying very well now and the Father has been around (but not much) to bring the food, I have observed that the Father will bring the food and when the baby is near drops it so that she must catch it.

Questions: When will the baby start hunting on its own or even attempt to? She calls out (crying or begging) on a regular basis looking for the Father. How will he teach her hunting skills if he is not around for her to observe.

I have had the best two years watching these hawks and so fortunate that they allow me into their world from a distance. I respect them and never want to interfere with the balance of nature.

I have great respect for John Blakeman, and I know that you are affiliated with him and I know between the two of you maybe you can answer my questions.

Sincerely,

Claire F Rutledge

Wakefield MA

John Blakeman sent in a prompt answer:

Claire,

Several points. If vultures took the young last year, the young birds were almost surely dead before the vultures got them. Red-tails are never preyed upon by turkey vultures. Black vultures (don't know if you have any of those in MA, probably not, as they are a more southern species) can be a bit more aggressive. But unless the eyasses were dead on the nest, the parents would have easily defended the young against the vultures. Let us know if you actually saw vulture predation. Very interesting if it was observed. I've never seen this, nor know of any such events in Ohio.

Secondly, don't be completely certain that the mother has disappeared. In summer, red-tails seem to frequently "disappear." They are still around, but they take hunting perches within tree vegetation, instead of sitting so commonly out on utility poles and fence posts. Last week I drove 60 miles along a four-lane into Cleveland. In fall, winter, and spring, I commonly see anywhere from four to a dozen perched red-tails. Last week: not a single bird. I've noticed this for 30 years. In June through September here in Ohio, red-tails seen sitting out on hunting perches are markedly less frequent. It appears that the population just implodes in summer. But the birds are still there, but just not as visible.

Why? l'm not sure. But it probably relates to availability of food for competent adult red-tails. These birds can capture just about anything they wish, and the roadsides are loaded with populations of plump voles, large field mice. By late morning, most adult red-tails in summer have easily captured two or three voles. They are done hunting and feeding for the day. They can simply go off and sit in the cool foliage of an oak or maple overlooking the landscape. Occasionally I've discovered these somewhat "hidden" birds, as their white breast can sometimes be seen in the foliage

So don't presume that your female is not present. She may start to appear in September and October when days shorten and more time must be spend on the hunt. Remember, red-tails do virtually all of their hunting while sitting on an open hunting perch.

Don't so much lament the loss of the first brood of this pair. This is very, very common. It appears that the vast majority of red-tails, at least in the Midwest and similar regions at the same latitude, fail in their first or second nesting attempts. Success requires that everything must be just so. The nest has to be well-constructed. Incubation must be continuous and attentive. Feeding the eyasses at the start can be problematic for parents who have never done it. In short, most red-tails have to try it out for a year or two before they get it right. After that, they are accomplished parents and will be frequently successful in ensuing years. But you have been watching apparently a typical young pair of red-tails.

Once the eyasses fledge, parents will seldom, if ever, give the food they provide directly to the young. As you've observed, it's dropped nearby, or even trailed along to entice the young to actively pursue the food. Have you seen the parent drop a still-alive animal? This entices the young to not only learn to attack the fleeing animal, but also to learn to kill it. The young have really no idea how to kill a struggling prey animal. Yes, they know that they should grab it. But where? In the head? At the tail? In the belly? The young birds have to learn what works, which is usually a head kill with the powerful talons. But their only instinct is to just grab the moving animal. They will have to learn that a talon puncture or severe squeeze to the head works best.

When will the young bird start hunting on it's own? Primarily only when the parents stop providing daily fare. When will a 16- or 18-year old kid stop spending allowance money and go out and get a real job? Only when Mom and Pop cut off the supply of free money.

And you've heard the forelorned cries of the ever-more neglected fledgling. You will never forget that sound. I hear it frequently out here in the countryside at this time of year. The hungry young red-tail wonders where today's food is. "Where are my parents and those voles they were bringing me last week? I'm HUNGRY!!"

Of course, "I'm hungry" in red-tail language is an incessant high-pitched "wheep, wheep" sort of call. It's just pitiful to hear. There is a mixture of both morbidity and selfishness to it. In late June and July, parents respond to it by providing food. But in late July or early August (at Ohio latitudes), the parents stop the routine and the young are left to their own hunting devices -- which aren't very significant.

This is when the young hawks get into real trouble. In more rustic times, when every farmyard had free-ranging chickens (and exceptionally fine-tasting -- I mean for humans), starving red-tails often couldn't resist these large meal targets. Hence the name "chicken hawk." Virtually all chicken predation was by starving first-summer red-tails.

I call these screaming hawks "wheepers," for their wheeping-sort of vocalizations. These are exactly the birds we falconers trap for the sport. They are easy to capture, and they are so appreciative that we provide the food that their parents terminated. All three of the last red-tails I trapped for falconry had been eating only grasshoppers before I took them into my care. A grasshopper diet portends a gruesome, lethal future for a wild red-tail. Remember, only 40% -- at best -- of red-tails that leave the nest will ever survive the first winter. Before winter, most die from their inability to successfully hunt and kill every day.

How, then you ask, will the young bird learn to hunt? It may not. The majority don't learn these lessons fast enough. And today, the main reason for this, just as it was before Europeans altered the North American landscape, is because young red-tails just don't have many unoccupied areas that they can fly into and find sufficient prey animals to support them. The good areas are already occupied by old, experienced adults. In August, they will drive out any young birds hanging around that compete with adults for food. The birds are dumped out on the street and kicked on their way out of the territory. Then, they've got to learn how to hunt very quickly. If, perchance, they wander into an area with lots of voles, they can learn how to hunt by the time cold nights hit in October. Otherwise, they will starve trying to eat grasshoppers or other inadequate fare.

And this, I believe, is why Pale Male, Sr. came into Central Park. When young and inexperienced, he wandered into this giant, prey-filled landscape in which no self-respecting adult would ever take up nesting residence. But Pale Make did, and the rest is history. In previous times he would have found a vacant, typical rural territory because red-tails were commonly shot, leaving openings for young birds to jump into. But today, very few hawks are shot or illegally trapped, so the countryside is saturated with adults. The young birds, such as the one you are watching, have a very difficult time living to adulthood. It's not the 1930s, 40s, or even the 70s or 80s out there any more. Life for red-tailed hawks is very different that it once was, and we are watching that in Central Park and elsewhere.

Sincerely,

John A. Blakeman

Monday, July 18, 2005

Redtail Molts: Questions & Answers


Ben Cacace, a long-time Central Park Hawk observer, sent me a question which I forwarded to John Blakeman. He answered, I asked for another clarification and he answered again. Below is the entire correspondence:

Marie,

I have a question for you concerning molting of
Red-tailed Hawks. Could you or Blakeman let me know
what the sequence of molting is for Red-tailed Hawks?
I have a few books at home but they don't go into the
details on the timing of the molt. I am wondering when
the juvenile starts molting the tail feathers. This is
related to the molting RT I saw perched on the South
Gate House of the reservoir recently. Only one half of
one adult tail feather had grown in. This was on July
15th 2005. Here is the quote I posted to eBirds NYC:

"At the reservoir on the top of the South Gate House
was a subadult Red-tailed Hawk. This RT is the first
I've seen that is molting from juvenile to adult. The
majority of the juvenile tail feathers were intact and
underneath the worn feathers, in the center of the
tail, is a half-length bright brick-red tail feather.
The iris of this hawk is light in color. It had a dark
belly-band and a dark head."

Even though it was very hot and it was on an asphalt
roof it spread itself out flat, wings stretched and
tail spread, apparently looking to absorb as much heat
as possible. This was done for a number of minutes.

Thanks in advance!

Ben



John Blakeman replied

Ben,
What you've seen, with the immature red-tail flying around with a single, half-descended red tail feather, is rather normal.
By this late in the season, the bird should have 4 to 6 red tail feathers in place. But the onset and progression of annual molting, both for immatures and old adults, can vary widely, for reasons not always clear. It seems that well-fed birds often start earlier and finish the molt early. Birds having difficulty finding food often start later and progress slowly. That's probably the case with the bird you are watching.
But don't be surprised to find several gaps in the tail where feathers have been dropped in a few weeks. In August, time gets short and molting sequences are usually advanced. I once had an immature red-tail that had a delayed molt (even though she had plenty of food from me -- I'm a falconer). Then, in late July and August she just seemed to drop feather after feather. In August she looked plainly ragged. But by October, she had a new, adult set of feathers.
The tail molt usually begins with a central feather, and then progresses outwardly as new feathers descend and harden.
Hope this helps understand what you've seen.
Keep me posted. Shoot any other RT questions my way.
Sincerely,

John A. Blakeman

I wrote Blakeman back:


John, I want to be sure I get it right. The immature bird discussed below is not a 2005 fledgling, right? This year's crop won't have any red in their tails until 2006??


Marie,
Right. I didn't make that clear. Any bird molting right now was alive and on the wing last year. This molting red-tail fledged in the spring of 2004. Every bird of every age has to take its feathers through a fall, winter, and spring before they molt out.
I also didn't point out that the new tail feathers will be about an inch shorter than the original brown feathers the bird left the nest with. By now, when molting birds are about one-third to half way through their molts, the tails can look a bit imperfect, with the older ragged feathers extending a bit beyond the bright new red feathers.
The same thing happens with the long primaries, the finger-like feathers on the tips of the wings. This is why first year red-tails, in their immature brown plumage, not only look larger than adults, they physically are -- in dimension, not weight. Because flight and leg muscles haven't completely matured when the birds fledge, the birds are able to fly with moderate ease with the longer feathers. This gives first year birds lighter wing loading. But with stronger muscles in the second year, the tail and wings molt out shorter. Hawk watchers should understand that first year red-tails look, and are, larger than the adults. They aren't as fast or strong, just bigger. They don't weigh as much, either.
But this is always a confusion for the unfamiliar. The presumption is that a small hawk is a "baby," and a big one an adult. Doesn't work that way. It's not size. It's weight that counts. What can the bird hunt and kill? That depends on muscles, and they develop more slowly than feathers.
So no one should ever be surprised to see a pair of eyasses about to fledge that appear larger than their parents. In size, they will be. That gets fixed in next year's molt.
Sincerely,

John A. Blakeman