nature vignettes: raptors

8/9/2019 Nature Vignettes: Raptors

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Dumb Luck

Captures Mystery Bird

on Film

I dont know why I took the photograph shown as Figure 1. One of the western crowscan be seen perched on the lowest branch of the foreground tree, but I doubt I was


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Figure 1

focusing on it. (My normal lens was on the camera; thats why I show such a largearea.) Its doubtful I was trying to capture the color of the setting sun against theheadland; the sky looks washed out. Jehoshaphat, you say, isnt it obvious that I wastrying to photograph that huge bird seemingly perched just above the fence? Maybe,but I dont even recallseeing that bird. Had I seen it, why would I have turned from it

(frame 8) and photographed two crows on the beach (frame 9). Had I seen it, I wouldhave taken every possible exposure, climbed the rock to look for evidence of a kill,then rushed the film directly to the lab. Then again, if Ididnt see it, why did I turn


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Figure 2

back and take the photograph shown as Figure 2 (frame 10)?

I know of two possible explanations for this seeming blank-out -- pneumonia, the latter

stages of which I was just about shaking off when these pictures were taken (earlySeptember), or early-onset senility.

The scene is the top of the rocky headland at the west end of White Beach inManchester-by-the-Sea. I photographed Figure 1 just as the bird appeared to belanding in the top of a small evergreen. That evergreen is only about twelve feet high,and its top might support the weight of a crow, but certainly not a bird this large. Itspossible that the bird was attacking something in the treetop. Those shapes on thehillside to the left of the fence (Figures 1 and 3), which may look like birds escaping

downhill, are simply leaves on a foreground shrub.

Some of the western crows (See my vignette, Flocks of Crows -- a Journal) were inthe vicinity. Figure 1 shows one of them perched in the tree at the end of the feeding

wall. Two others were down on the beach not far from where I was standing. Ishould think all three crows would have been able to see the large bird atop theheadland, yet I recall none of them showing any excitement. The two on the beach

were definitely unperturbed.


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Figure 4

Figure 3

In Figure 2 the large bird has landed on the far side of the fence. Again, had I seen thatbird, surely I would have climbed the promontory to get a closer view of it or to lookfor signs of a kill. My first awareness of the bird was when I got my pictures from thelaboratory on 17 September 2003. I wasted no time climbing the promontory to checkfor signs of a kill (none) and to measure the height of that fence (six feet from ground

to top horizontal bar). Thats half an inch in Figure 3, and the birds wingspread is halfthat again. The evergreen, which appears to be directly beneath the bird, was thesame distance from my camera as the left-hand corner of the fence. That is to say, thebird is no closer to the camera than the fence corner. Its wingspread appears to beeight to nine feet, which rules out all but turkey vulture or bald eagle. That the crowsshowed no excitement would suggest turkey vulture, but that species has a maximum

wingspread of six feet. The only bird native to this area whose wingspreadapproaches that shown in Figures 1 and 3 is the bald eagle.

Figure 3 is an enlarged section of Figure 1. Figure 4 is an enlarged section of Figure 2,where the bird had dropped to the ground.

I have a friend who lives on this hill. When I described this incident and hazarded theguess that the bird was a bald eagle, my friend said that one of her neighbors hadrecently seen a bald eagle outside her home.


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Playful Interactionbetween

a Peregrine Falcon

and a Flock of Crows(17 August 2003) I had just fed the eastern crows at the Private Path feeding tree (Seemy vignette, Flocks of Crows -- a Journal). While the crows were still in the tree, fiveor six mourning doves flew into the treetop. From somewhere in the salt marshbeyond the tree, a peregrine falcon (Falco peregrinus) flashed into view and attackedthe doves. This spooked the crows into flight, which apparently caused the falcon to

miss its kill, because it turned sharply andmade a pass at the crows. I expected tosee a crow injured or killed, but the

peregrine broke off its attack andperched in the Private Path tree for somethirty minutes. During all this time, fourof the crows perched in the same tree.They didnt seem concerned with

watching the falcon. I believe they werejust waiting for me to feed them again.One crow was perched on a branch justabove the falcon, with no conflict oraggression apparent. For most of thistime, the crows were quiet. Peregrinesand crows may co-exist because theyreabout the same size, and the peregrinesare usually outnumbered.

The falcon was slate gray above, pale towhite below, with a barred breast, so I concluded that it was a male. The bird wasperched in a fairly dark location, well shaded from the sun. I moved as close as Idared, fifty to sixty feet, and photographed it using my zoom lens. The prints look fairlysharp, but my scanner just doesnt resolve the images well enough. Using Paint ShopPro 7, I enhanced the scans to the best of my ability, but the focus remains soft. This

lens has always given me trouble.

Now and then the falcon did pursue a crow, but I think it was done in play, for surely aperegrine could catch a crow over a distance of fifty to a hundred feet. Each crowhaving survived the chase, several crows would gang up and chase the falcon, but notangrily, as they do with red-tailed hawks. I sensed that the crows and falcon weresimply playing. Again, I apologize for my lousy photography.


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Peregrine falcons (a.k.a . duck hawks) are known for swift flight and dramaticstoops, which make them the favorite among falconers. Theyre among the mostbeautiful of raptors, and are found worldwide except in Antarctica. In my youth,peregrines were widely believed to be capable of 200-mile-per-hour diving speeds, butthe technology needed to prove or disprove this was not available. The subject has

been controversial, with various sources rating peregrine diving speeds from 100 to250 miles per hour. More recently, the 200+ figure has been well validated. Trainedperegrines have been filmed flying with skydivers, and speeds over 200 miles per hour

were recorded. American researchers have recently (2003) been using lead weightsdropped from high flying aircraft and pursued by trained peregrines. One bird's topdiving speed has been clocked at 389 kilometers per hour (240 miles per hour). TwoOhio Division of Wildlife volunteers, using a properly calibrated radar gun, recentlyclocked a stooping peregrine at 261 miles per hour.

This is not to say that peregrines alwaysplummet out of the sky at maximumspeed. On the contrary, they control theirattack speeds by opening or closing their

wings to vary drag. In one study usingtiny accelerometers attached to the birds,forces in excess of 25 Gs were recordedduring the falcons aerial maneuvers.

All the foregoing figures relate to divingspeeds. In level flight peregrines arentparticularly fast. For example, they can

be outflown by pheasants and racingpigeons, the latter being capable of 100miles per hour in level flight.

During both World Wars, peregrines were slaughteredbecause they threatened carrier pigeons used by themilitary. Inadvertent but even more deadly was the

widespread use of pesticides, which broughtperegrine falcons close to extinction. The peregrinefalcon recovery program has been the most dramaticand successful of all national efforts to helpendangered species. People the nation over,including more than half of the state wildlife agencies,the U.S. Fish and Wildlife Service, and importantprivate organizations such as the Peregrine Fund,have made important contributions to this success.


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Photo Courtesy of Working for Wildlife

In my area peregrines are rare migrants, usually found along the coast, so I considermyself fortunate to have seen two in recent years. The other one was sighted farinland, in Burlington MA, in the crowded office park adjoining Burlington Mall. I saw itoutside the Lahey Clinic, perched on a dead branch of a large tree at 11:15 AM on 15

January 2002. It was being harassed by a lone crow. My binoculars and bird guide

were half a mile away in my car, so I couldn't make a positive identification. When Iwent inside, I told the Cardiac Rehabilitation nurses about the raptor. They said it haddefinitely been identified as a peregrine falcon, and had been seen many times. Thenurses think the falcon preys on the abundant pigeons in the office park. When I leftLahey at 12:45 that day, the falcon was still there, sans crow. I recalled the peregrinelooking quite a bit larger than the crow, so I would guess that it was a female. Im toldthat this falcon was resident in Burlington Mall through the winter of 2001-2002. Thesupply of pigeons must have been good.

[An aside] On Easter Sunday of 2002, my son and daughter-in-law were standing withme in the parking lot of Burlington (MA) Mall. We had just finished lunch, and werepreparing to part, when a raptor appeared high overhead, then went into a shallowdive and accelerated to a very high speed. The wind at ground level was against thebird, but at altitude the bird must have had a favoring wind to reach such speeds. I'llswear it approached one hundred miles per hour. On the strength of this speed, weimmediately saidperegrine falcon , but I thought the wings too broad, and took my birdguide from the car. My son agreed that the wings had looked nothing like aperegrine's, more like a red-tailed or a red-shouldered hawk. The hawk returned from

wherever it had sped off to, and perched on one of the high light towers near thehighway. (The last photo shown heredoesnt relate to the bird seen by me and

my children. I close with it just becauseits a marvelous shot.)

http://oddsbodkins.posterous.com/


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nature vignettes: raptors

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