| A cliff swallow. |
Researchers Charles and Mary Bomberger Brown have been studying cliff swallows since the 1980s. Over the years, they have traveled to many swallow colonies built under bridges, trying to learn more about the birds' behavior. They have made an interesting discovery: since the start of their study, the number of swallows killed by cars has gradually gone down, with only four found in 2012. The average length of the birds' wings has also been decreasing. The data suggest that cliff swallows have adapted to living near highways. Shorter wings may give them greater agility and allow them to take off more quickly, decreasing their chances of becoming roadkill.
NOS Themes:
- Science is tentative. Before concluding that the cliff swallows were better at surviving due to their shorter wing spans, the researchers eliminated other possible causes such as smaller swallow populations or an increase in scavengers eating the roadkill. They have not ruled out the possibility of other characteristics being selected for, such as more cautious swallows.
- Science is observable. The team was able to back their findings with quantitative data giving the numbers of swallows they found hit by cars each year.
- Science is consistent. The trend of declining numbers of dead birds has continued all this time.
Wow, that's interesting how swallows have evolved to survive better by highways. Really, when I think of evolution, I think of millions of years ago when humans evolved from apes, but evolution is happening right on our modern highways!
ReplyDeleteI found on a website of a plant that has also evolved recently. A South African flowering plant known as the Rat's Tail has evolved to allow pollinating birds to dip their beaks into its flowers. The plant has evolved to grow a firm stalk in a perfect perching position for feeding. Evolution is happening very much today and in many different places.
Website Link: http://www.popsci.com/node/56803
This is really cool to see a situation of evolution that fits our modern view of life. It is amazing how natural selection occurs within a species. Depending mostly on luck to occur is just another one of natures miracles.
ReplyDeleteThat is really cool to see evolution happen in modern times. I found an article that said swallows that live near big roads need small wings for quicker dodging of cars. In 30 years of studies, a group of researchers found that swallow wing size is decreasing and the number of birds killed by cars decreased.
ReplyDeletehttp://dailyme.com/story/2013031900000871