Wednesday, November 07, 2007

Redtails and Squirrels - Q & A with Blakeman

Photo courtesy of -- Nov 5, 2007

A question for John Blakeman just arrived from Bill Trankle, a correspondent from Indianapolis . Below, the Q & A:

Bill writes:
Marie, today showed a shot of one of the immature hawks (the Washington Square bird I believe) where the hawk is apparently sitting on a squirrel nest (that big, untidy ball of leaves). Since John Blakeman has mentioned that squirrels are not a common source of food for red-tails, I was wondering if he'd ever observed hawks attacking squirrel nests before. Of course, without knowing the shot's context, it could be that the juvenile was just curious, or perhaps thought it a nice soft spot to land!

The reply:
Marie and Bill,

Red-tails in the wild do not commonly kill squirrels. They are too big, have very tough skin that is an effort to rip away when eating, and they can bite deeply into a toe or tarsus (ankle).

Time after time I have seen our giant Ohio fox squirrels run around in a tree or woodlot in full view of a sitting red-tail. The hawk seldom pays any attention. There are any numbers of photos on of Central Park squirrels going eye to eye with a local red-tail.

However, red-tails can and do attack and kill squirrels, either when they are hungry (having missed a meal because of bad weather on previous days), or perhaps because they want some different meal fare from time to time.

Do red-tails attack squirrel nests? I've never seen it, but my falconer friends who hunt squirrels with red-tails are very familiar with this behavior. Squirrel-hunting falconry red-tails soon learn that fleeing squirrels often duck into their large agglomerations of sticks and leaves, the squirrel "nests." The red-tail, being rather intelligent, realizes that the enclosed squirrel is protected only by lose leaves and small twigs, so the bird drops right on to the nest, or attacks it from the side, punching it, attempting to dislodge or grab a squirrel inside.

So yes, red-tails that have learned the habits of squirrels can attack a squirrel nest, often with some success. I think this might happen more often in New York parks than out in rural areas. NYC red-tails have no opportunities to take four or five field voles, the sustenance food of these birds in rural areas. Voles don't live in mowed turf areas.

Consequently, the urban red-tails have had to adapt to the prey there, which includes all the usuals, pigeons, rats, and an occasional squirrel. These tree rodents are surely seen each day by the hawks, so their every move and behavior has been much-studied by the local hawks. If Pale Male or Lola decide to have something different for lunch, a known squirrel nest could be easily punched to see what comes out.

--John Blakeman

Monday, November 05, 2007

Comet Holmes getting even bigger

Photo Gallery: 'Once-in-a-Lifetime Event'

From the AOL web site:

Paul Lewis, director of astronomy outreach at the University of Tennessee, is drawing students to the roof of Nielsen Physics Building for special viewings of Comet 17P/Holmes.

Astronomers speculate that Comet 17P/Holmes has suddenly brightened because a collapse caused by sinkholes on its surface has sent a bubble of sunlight-reflecting dust and ice into space.

The comet is exploding and its coma, a cloud of gas and dust illuminated by the sun, has grown to be bigger than the planet Jupiter. The comet lacks the tail usually associated with such celestial bodies but can be seen in the northern sky, in the constellation Perseus, as a fuzzy spot of light about as bright as the stars in the Big Dipper.

"This is truly a celestial surprise," Lewis said. "Absolutely amazing."

Until Oct. 23, the comet had been visible to modern astronomers only with a telescope, but that night it suddenly erupted and expanded.

A similar burst in 1892 led to the comet's discovery by Edwin Holmes.

"This is a once-in-a-lifetime event to witness, along the lines of when Comet Shoemaker-Levy 9 smashed into Jupiter back in 1994," Lewis said.

Scientists speculate the comet has exploded because there are sinkholes in its nucleus, giving it a honeycomb-like structure. The collapse exposed comet ice to the sun, which transformed the ice into gas.

"What comets do when they are near the sun is very unpredictable," Lewis said. "We expect to see a coma cloud and a tail, but this is more like an explosion, and we are seeing the bubble of gas and dust as it expands away from the center of the blast."

Experts aren't sure how long the comet's show will last, but estimate it could be weeks - if not months. Using a telescope or binoculars help bring the comet's details into view, they said.