Saturday, January 20, 2007

Tyler to Blakeman: But hawks deter pigeons elsewhere!

Pale Male with morning pigeon at Great Lawn --Jan 18, 2007
Photo by Lincoln Karim

The next exchange between the Oklahoma guy with a pigeon problem and hawk expert John Blakeman. [For part I, see previous post]

Thank you very much for your prompt and thoughtful response. It is disappointing to hear that I won't necessarily be able to justify implanting some nesting hawks for their pigeon prowess, but nonetheless the research has been fascinating up to now. These birds really are amazing!

However, I would like to ask of you a couple more questions if you don't mind. I can only assume that you are familiar with the Harris Hawks being used to clear pigeons from the public squares in London. Or perhaps the use of "skygaurd" Peregrine Falcons to clear pigeon and other pest birds from runways so they don't get sucked into a jet engine. What is it, essentially, about these projects that seem to have so much success? Is it perhaps active Falconry? Or is it simply the basic math of reproduction that makes pigeons with a solid high-calorie food source seemingly impossible to deter?

In any event, thank you again for your assistance. And keep up the interesting work you do with these fabulous and impressive creatures.

All the best,

Tyler F. Forve
Associate Business Manager Cargill Animal Nutrition - Southwest District Oklahoma City, OK

Blakeman's reply


Yes, the use of a Harris' Hawk against park pigeons works, as does the use of peregrines chasing off pigeons from airfields. One would think, then, that these should work at your facility. Here're the essential differences.

Falconry-trained Harris' Hawks can easily chase off pigeons in a city park. But as soon as the falconer and his bird leave, the birds will be right back. So, for incidental or event problems with pigeons, the hawk works. But for continuing control, it won't.
The same for bird control at airports by falcons. A soaring falconry hawk will definitely push off any birds below. If the falcon is flown daily over the airport, the pigeons, geese, and other birds will learn this schedule and go to other areas when the falcons are aloft.

That's the essence of the matter. The pigeons at your facility live there, they don't just come in from afar. Like similar grain-handling facilities, your pigeons regard your site as home. They know all the nooks and crannies in your buildings and machinery. Actually, a falconer flying a trained peregrine over your facility will make the pigeons disappear---but just while the hawk is aloft. The pigeons will poke their eyes out from behind where they are hiding and as soon as they don't see the hawk aloft, they will be right back.

Hawks are not able to reduce actual pigeon populations. At best, they can only temporarily cause the pigeons to stay hidden or parked away for a time from the immediately "protected" site. That works very well at airports, and London parks. but is not the real solution for your site. Park and airport pigeon-chasing hawks work only for a time, usually only while the falconer stands on the ground and controls his hawk. When the hawk is retrieved and put back into its mews, the pigeons come right back doing their typical pigeon things.

You need to keep pigeons away 24/7. Hawks and falcons can't do that. They can only divert the birds for a few hours or so, while the hawks remain on site.
But again, I commend you for your intelligent consideration of ecological solutions.

John A. Blakeman

Friday, January 19, 2007

A job offer for Pale Male

PM & pigeon - January 15, 2007
Photo by Lincoln Karim

I received the letter below and promptly forwarded it to John Blakeman. I had a feeling he'd know how to answer. and, as you can see in his response to Tyler, he did.


I was hoping to glean some information from you about the feasibility of providing a roost for red-tailed hawks in the Oklahoma City area. I manage a feed mill for Cargill Inc. and we have something of a pigeon pandemic due simply to the large amount of pigeon-perfect food that is a by-product of our industry. We are looking for a clean, humane and environmentally sound method of deterring pigeons from our area and I was wondering if you may have any information that may give this project wings--as it were.

Any support you could provide would be greatly appreciated.

All the best,

Tyler F. Forve

Blakeman's response:


Marie Winn graciously referred your inquiry to me, a frequent contributor to her wonderful website.

Your approach to pigeon control at your facility is a laudable one. But unfortunately, red-tailed hawks seldom (except in Central Park and other concentrated city areas) ever capture or consume any number of pigeons. Even in Central Park, their control or diversion of pigeons is inconsequential. A resident pair of red-tails, at best (during the non-breeding seasons) will capture only a single pigeon a day. They cannot pluck off more pigeons than are being replaced by normal pigeon breeding, which as you know is profuse.

Most importantly, even if a pair of red-tails took residence at your facility, they would most likely then soar out into the countryside to hunt their preferred (and easy to catch) prey, field voles and mice. As much as we'd like, the red-tailed hawk won't divert or reduce your resident pigeons.

The only species that might would be a pair of peregrine falcons. I erected a peregrine falcon nestbox on a grain handling and processing facility here in Huron, Ohio, and the pair really caused apprehension with the hundreds of pigeons there. But even so, the peregrines did not really reduce any real pigeon numbers. Just as in New York City and other areas with both red-tails and peregrines, the pigeons soon learned to spot the approaching hawks and took successful evasive actions. In the case of red-tails, the pigeons just fly up and away, turning to the side as the hawk approaches. Any pigeon not paying attention is likely to be captured by the hawk. But most escape.

With the sighting of a peregrine, pigeons will remain on the ground where a falcon refuses to attack. If pursued while in the air, the pigeons will circle back behind the swooping falcon, making it difficult for a capture. I marveled for many hours as the peregrines in my area dove at local pigeons. I never saw a single one captured.
Therefore, neither red-tails nor peregrines will solve the pigeon problem. Pigeons and peregrines evolved together since the Pleistocene Age in the Old World. The peregrines can capture enough to feed themselves, but never enough to reduce or eliminate the population.

Red-tails are just learning to attack and capture pigeons. Because they are much larger and less maneuverable than the aerially adroit falcons, our big hawks are even less successful with pigeons than the falcons.

Consequently, neither species of hawk will be a solution to your pigeon problem. I'm not certain that there is one.


John A. Blakeman

Thursday, January 18, 2007

What's with Charlotte and Junior?

Charlotte on the X of the ESSEX HOUSE sign on Central Park South
Photo taken in November, 2006 by Bruce Yolton

Sally Seyal of Prospect, Kentucky, a website correspondent, sent me a note a few weeks ago wondering why there was no news about Junior and Charlotte. I wrote to a few of the Central Park South hawkwatchers and was waiting for more complete reports. I'll post some of their replies when they come in. Now here's a reassuring note from Bruce Yolton:

Bruce Yolton writes:

The Central Park South hawks are doing just fine. They are hard to photograph and study this time of year, so most of the hawk watchers spend their time with Pale Male and Lola or the number of "floaters" seen this time of year.

The Central Park South hawks like the very tall buildings along Central Park South, Central Park West and into the city a few blocks. This time of year they are usually seen as little specs on top of these tall buildings.

Come late winter and early spring, we'll see them more frequently and you will see some reports.

I have been reporting about them. My last photographs are from November. On my site, [] scroll down to the Categories section on the left panel, and click on C.P.S Red-tailed Hawks.

Tuesday, January 16, 2007

Party Crashers: a Central Park wildlife story

Photo by Eleanor Tauber

Party Crashers

On a fine September night two or so years ago three raccoons dined among a crowd of gussied-up bird lovers at the Central Park Boathouse. The occasion was the New York City Audubon's grand benefit party honoring Pale Male & Lola. Appearing in the bushes behind the Boathouse’s outdoor terrace at about 9:45 p.m., the rather under-dressed party-crashers consumed large quantities of chicken and pasta that were furtively offered them by several invited guests.

Though the raccoons ate noisily, their benefactors managed to close the terrace doors, thus keeping the animals’ little growls of bestial contentment from disturbing the benefit honorees, Mary Tyler Moore and Parks Commissioner Adrian Benepe whose prepared remarks were being delivered at just that time.

The thick-tailed, black-masked members of the Procyonidae family, one that also includes kinkajous, coatis, cacomistles, ringtails and olingos, are year-round residents of Central Park. They are far from uncommon there. Some officials suggest that up to fifty raccoons permanently live in the park, and it may be twice as many. Nobody’s ever figured out a way to do a raccoon count.

Five years earlier more than twenty-five raccoons had been found dead in the northern part of the park. Necropsies revealed multiple lacerations and puncture wounds, probably inflicted by dogs. There were rumors of two large, muscular dogs, possibly Rottweilers or Doberman Pinschers, ranging through the North Woods. Once, again according to rumor, the dogs were seen running out of the park and into a waiting car, suggesting that a pair of vicious dogs were being loosed in the park to kill for the amusement of their sadistic owners.

Why come up with this bizarre scenario? Perhaps the killers were simply feral dogs, strays, Yet none of the park’s population of stray dogs, known well by Parks Department workers, was deemed capable of winning a fight with a strong, aggressive fifteen to twenty pound raccoon.

It is known that raccoons will savagely defend themselves when attacked. But they pose no danger to humans. There has never been a case of a human attacked by raccoons in Central Park, It is as unlikely an event as a squirrel biting the hand that feeds [and feeds and feeds] him. Tourists in particular are charmed to come across a big, wild, woodland creature like a raccoon in the heart of a big city. Fortunately, the dog attacks ceased as mysteriously as they started, and the species seems to have bounced back to its normal number in the park.

The three raccoons who attended the Audubon benefit at the Boathouse seemed to like the chocolate petit fours and the miniature cheesecakes from the dessert table best. They picked up each little pastry with their hands, and delicately placed it in their mouths, a behavior described in an authoritative text, Walker’s Mammals of the World, as characteristic of the species [the manual dexterity, that is, not the consumption of goodies.]

Procyon has a well-developed sense of touch...The hands are regularly used almost as skillfully as monkeys use theirs,” say the authors of Walker’s Mammals [none of them, oddly enough, named Walker] adding an observation that makes a lie of the raccoon’s scientific name, Procyon lotor. The Latin words mean “washing bear”. Yet the book goes on to say: “Although raccoons have sometimes been observed to dip food in water, especially under captive conditions, the legend that they actually wash their food is without foundation.”

The raccoon’s versatile hands—one might more properly call them front feet—are a remarkable adaptation that allows these highly successful animals to reach into small spaces or turn over stones while looking for prey, as well as to catch and hold onto small animals, fish and a variety of invertebrates out in the open. Their clever hands also enable raccoons to perform the single act they are most famous [or infamous] for in the human community: opening garbage cans no matter how securely closed. Raccoons don’t have to work too hard at this in Central Park. Most of the park’s garbage cans are easily opened. After dark, raccoons are often seen climbing in and out of them, carrying booty off to eat on nearby branches. Sometimes a couple of animals will work in concert to knock a large garbage container over. Then they can dine on the spot with the greatest of ease. They just crawl in and chow down.

Back at the Boathouse terrace, after the three bandit-masked, ring-tailed, pointy-muzzled members of the order Carnivora had eaten a truly awesome number of rich little confections, some party guests were concerned for the animals’ health. These fears were groundless. Boathouse employees reported that the three were seen again at another party the evening after the Audubon benefit. They were in fine fettle, the men reported, though they seemed a little peckish if not downright hungry.

Monday, January 15, 2007

Osage Oranges: I know I said it was the last one but...

Two more letters;
The really last Osage Orange post.

Hi Marie,

I married and set up housekeeping in the late 60's. You may remember this
as a time when macrame was in vogue and homes often displayed wall
pockets made of clay and hung from hooks with leather lacing. These
decorative objects often contained natural plant materials (weeds) and were
considered attractive. Osage oranges could be sliced horizontally, dried, and
strung on wire stems to look like flowers in dry displays. Thank goodness
those days are long gone.

Pat Floersch


. . . I did some research online and it turns out the Native Americans used the wood to make great hunting bows. Here's some info from Wikipedia:

The trees picked up the name bois d'arc, or "bow-wood", because early French settlers observed the wood being used for bow-making by Native Americans. The people of the Osage Nation "esteem the wood of this tree for the making of their bows, that they travel many hundred miles in quest of it," Meriwether Lewis was told in 1804.

I'll never forget my first experience with these fruits. I was only a kid in Prospect Park when I pointed out to my parents that they must be oranges because they smelled just like them. It's a good thing they told me not to eat them.

All the best,

Ciro Monaco Jr.

Sunday, January 14, 2007

Redheaded Woodpecker update and Woodpecker Biology

The Riverside Park Redheaded Woodpecker

photo by Barrie Raik

Update: This morning around 9 am the woodpecker looked more bedraggled than in Barrie's photo above. It was mildly raining. He was caching something fairly high up [about 12 ft.] in his usual tree [Elm?] just off Riverside Drive and 92nd Street, between park wall and the Drive. Very easy to find. Also there, Sandra Maury, one of the Early Birders.

More on Woodpecker biology:

A note from regular correspondent Nan Holmes referring to an article I posted a few days ago about how woodpeckers' brains are adapted to withstand intensive drilling

Dear Marie,

Never have I gone to a doctor but that I get conflicting opinions. And so it is here. My wonderful niece Kelly is in her final year at U of Georgia Veterinary School, and is currently finishing a round on ophthalmology. I sent her the woodpecker info and she showed it to her attending physicians. Below is his (her?) brief comment on intraretinal hemorrhages.

Regards, Nan Holmes

The niece replied:

Very interesting stuff. I showed it to my attending doctor on ophtho, and she did mention that birds do not have retinal vessels, so the intraretinal hemorrhages wouldn't be possible. Any hemorrhage would probably be subretinal (below the retina).

Comment from Marie:

Someone should write a note to the British Journal of Ophthalmology. Unless, of course, Kelly's attending physician is wrong. It happens. Any ornithophthalmologists out there?