“Her Last Flight” or “Evolution via Roadkill”

"Her Last Flight..."
It appears that this pigeon took a blow from the rear from an auto while trying to alight from the pavement. (Image made by me in Baltimore in 2010).

I thought that the following article made for interesting reading, in light of the fate that befell the bird in the above image. The article could lead one to speculate on how the pressures of natural selection are changing birds like pigeons and sparrows in an urban environment.

Evolution via Roadkill (March 18 2013):

Cliff swallows that build nests that dangle precariously from highway overpasses have a lower chance of becoming roadkill than in years past thanks to a shorter wingspan that lets them dodge oncoming traffic. That’s the conclusion of a new study based on 3 decades of data collected on one population of the birds. The results suggest that shorter wingspan has been selected for over this time period because of the evolutionary pressure put on the population by cars.

“This is a clear example of how you can observe natural selection over short time periods,” says ecologist Charles Brown of the University of Tulsa in Oklahoma, who conducted the new study with wife Mary Bomberger Brown, an ornithologist at the University of Nebraska, Lincoln. “Over 30 years, you can see these birds being selected for their ability to avoid cars.”

The Browns have studied cliff swallows (Petrochelidon pyrrhonota) in southwestern Nebraska since 1982. They return to the same roads every nesting season to perform detailed surveys of the colonies of thousands of birds that build mud nests on bridges and overpasses in the area. Along with studies on living swallows—counting birds and eggs, netting and banding individuals, and observing behaviors—the Browns also picked up swallow carcasses they found on the roads, in the hopes of having additional specimens to measure and preserve. They hadn’t planned studies on roadkill numbers, but recently they began to get the sense that they were picking up fewer dead birds than in the past.

When the researchers looked back at the numbers of swallows collected as roadkill each year, they found that the count had steadily declined from 20 birds a season in 1984 and 1985 to less than five per season for each of the past 5 years. During that same time, the number of nests and birds had more than doubled, and the amount of traffic in the area had remained steady.

The birds that were being killed, further analysis revealed, weren’t representative of the rest of the population. On average, they had longer wings. In 2012, for example, the average cliff swallow in the population had a 106-millimeter wingspan, whereas the average swallow killed on the road had a 112-millimeter wingspan.

See: Evolution via Roadkill

Violent video games under scrutiny after Newtown, Conn. school shootings

Video-game makers and retailers are facing growing pressure from Washington and advocacy groups concerned about possible links between violent games and tragedies like the school massacre in Newtown, Connecticut. A bill introduced Wednesday by U.S. Senator Jay Rockefeller directs the National Academy of Sciences to examine whether violent games and programs lead children to act aggressively, the West Virginia Democrat said in a statement. He will also press the Federal Trade Commission and Federal Communications Commission to expand their studies. The advocacy group Common Sense Media cheered the moves.
See Violent video games under scrutiny after Newtown, Conn. school shootings

Before the creation of video games people went to amusement parks and enjoyed themselves taking shots at mechanical targets. This photo (below) shows the remains of one such shooting gallery that had existed in Glen Echo Maryland. I don’t believe anyone has suggested that such recreational activity in amusement parks ever led to acts of mass murder, as some are suggesting is the case with these first person shooter video games.
Abandoned Amusement Park Shooting Gallery (Detail)

Remembrance of Physics Experiments Past…

A heavy camera to hold...

The human mind is certainly remarkable in its ability to retain long term dormant memories.
I've been reading the book "For the love of Physics" which is the autobiography of the physicist Walter Lewin. (cover shown at left)  I've also been watching several videos of him delivering lectures on physics to undergraduate students at MIT. I majored in physics in college, so there was an element of faint recollection watching him explain the basic principles of mechanics, especially the motion of a pendulum.
I recently purchased an old Polaroid camera at a thrift shop (see image at right). Fooling around with the camera brought back memories of a physics experiment that I did in college where I documented the movement of a double pendulum by making time lapse exposures with a Polaroid camera. What startled me was being able to recall this activity from 45 years ago that I had not thought about in 45 years! It's like this memory had remained dormant for 45 years, awaiting only the proper stimulus (reading Dr. Lewin’s book and fooling about with the camera) to return it to my conscious thinking.