Saturday, November 03, 2007

Dogfight in the sky-- Q & A

courtesy of Palemale.com -- Nov2, 2007

Q:

Hi, John,

PaleMale.com has some photos today of the young Washington Square hawks engaging crows. Never having seen this type of activity, I am wondering about the hawk's position. Is it one of these things like an aerial "dogfight", with loop de loops, etc?

Thanks,

Karen Anne Kolling
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A:

Karen,

I, too, saw those crow and hawk photos.

The hawks were "defending" themselves, but not with any deadly intent. For the hawks, crows are merely pestiferous and obnoxious interveners in the otherwise calm and peaceful (read that as mere sitting or soaring) lifestyle that red-tails prefer.
The obnoxious crows disrupt the calmer activities of red-tails.

So there's little to no chance a crow would be snatched out of the air by the hawks. The crows are very cognizant of the hawks' ability to reach out and grab something from the air, so they remain always just beyond the reach of the hawk.

The photo of the hawk on it's back looks menacing, and that's visual intent on the part of the hawk. After being pestered by the crows that had continued to come up on the hawk's back, it instantly flipped over and displayed its feet and talons. It was a bit of red-tail anger. I can imagine the mental cursing of the big hawk as it fended off the clever crows.

I find it interesting that these immatures were lingering in Washington Square park. Right now we are at the height, or beginning of the tail, of the red-tail migration, depending on the location and latitude in the East and Midwest. These are surely migrants passing through from the north. Why have they spent some time in Manhattan?

Two possible reasons. First, the weather, the atmospheric column, may have changed and made southerly gliding at altitude difficult. For a time, wind and air conditions aloft may have been unfavorable, making it hard to stay in the air. When required, red-tails can fly in even the most unfavorable wind conditions. But because they are so big and heavy, this exacts a large energetic price. For a local resident, a day's fight against difficult winds is of minor concern. The bird can sit around in a local tree the following day and regain lost energy.

But for birds in migration, it's simply best to "drop out," to fall down to the surface and wait around until favorable winds appear. That's most likely the reason these immatures were hanging around in Washington Square park

But additionally, a second reason, may be that while lingering for half a day or so, they discovered the ample and vulnerable populations of rats and slower pigeons. Red-tails migrating for the first time have never been "to the South." Everything is new to them, and they've got to take advantage of every survival opportunity. If they see a multitude of young rats skirting the edges of lawns in New York City's parks, here will be reason to linger in a migratory interlude.

And it's now November, a time when red-tails at more northern latitudes, such as New York City and my northern Ohio, tend to settle for the winter into open habitats with prey. There is the possibility that these birds may winter in NYC.

One last point. Here in northern Ohio, there was an exceptional population of immatures this summer. Very large numbers of eyasses were produced last spring, because of favorable weather and prey conditions. That may have been the case in New England, too, thereby accounting for these several immature hawks now in the park.

Sincerely,

John A. Blakeman

PS from Marie: John Blakeman makes the assumption that the hawks in Washington Square Park are migrants passing through from the north. I think it's more likely that these are local birds from a nearby nest. I wouldn't be surprised if Bruce Yolton has the scoop --I know he's been photographing these hawks and posting pictures on his web site http://urbanhawks.blogs.com/