Slashdot Mirror
Roadkill Forcing Cliff Swallows To Evolve
sciencehabit writes "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."
That will be the downfall of your species. Those who march in front are merely the meat-shields for the warriors that follow, the first torn down by the musket balls and horse mounted cavalry while those behind remain to actually fight.
The preceding post was not a Slashvertisement.
If I keep on smacking my kids, their arms will get shorter?
...And this is yet another proof that God exists. My prayer circle has spent the last 10 years asking for Divine intervention to halt the senseless deaths of road-adjacent animals. Thanks to our unceasing intervention, He knew to trim a wee bit off the tip of every bird's wings (gradually, of course, so that mommy birds would still recognize their babies - and left longer wings on the sinner birds so that they would die and serve as a warning to others). Praise Jesus!
What is the new air speed velocity of an unladen cliff swallow?
I was driving up in the mountains a year or so ago and saw a chipmunk run out into the road between me and the car coming the other way. Now normally this is pretty much certain doom for the chipmunk, but this one stopped calmly on the yellow line, stood up and waited for us to pass before continuing. I've always wondered if the evolutionary pressure of traffic combined with their short generation cycles would lead to critters less likely to become roadkill. Guess I have my answer.
I'm trying to teach myself to set people on fire with my mind... Is it hot in here?
Yes, this may be due to evolution, not of the birds, but the automobile.
To generate increased fuel economy, today's automobile is a lot more streamlined than ones of the past. So there is less air disturbance. It may be that the birds with smaller wings are not affected by the turbulence as much as the larger winged birds are now, and can thus survive an encounter, whereas in the past, there was enough turbulence to affect the birds regardless of wingspan. Also, changes in traffic patterns and vehicle types changes the exhaust, which changes the local plant life, which changes the insect life, which ultimately changes the birds.
While it is simple to observe that long winged birds are being disproportionately killed and that the population's wingspan is growing shorter, and conclude that some sort of selection (Is it natural selection when birds are hit by cars?) is taking place, the reality may be quite different.
When our name is on the back of your car, we're behind you all the way!
http://www.gallup.com/poll/155003/hold-creationist-view-human-origins.aspx
"Forty-six percent of Americans believe in the creationist view that God created humans in their present form at one time within the last 10,000 years. The prevalence of this creationist view of the origin of humans is essentially unchanged from 30 years ago, when Gallup first asked the question. About a third of Americans believe that humans evolved, but with God's guidance; 15% say humans evolved, but that God had no part in the process."
I had to go through a set of lights by a couple truck stops back in the day more than once a week. I noticed grackles (crowish kinda birds) that would wait on the posts or nearby for the lights to turn red. Then they would jump down and pick the grasshoppers and bugs out of the 18 wheeler grills. When the light turned green, they all flew back up and waited. They were quite well fed.