Swallows are adapting to car traffic by shortening wings.
According to research by scientists from the University of Tulsa in Oklahoma and the University of Nebraska in Lincoln, cliff swallow birds have evolved to have shorter wings.
Extrapolating from data that shows the bird’s wings have shortened since research began in 1982, scientists speculate that the physical change may be an adaptation to avoid being killed by oncoming traffic.
Their data also shows that bird bodies killed by traffic generally have longer wing spans.
Shorter wings allow for more maneuverability.
Besides dodging vehicle traffic, having shorter wings may also make the birds better suited to hunt insects associated with human agriculture.
Although traffic has increased, the cliff swallow population has also increased, and the number of cliff swallow deaths caused by road kill has declined.
Charles Brown, a biologist at the University of Tulsa, Oklahoma said: “I don't think necessarily road mortality is the sole cause of this. I think there are other factors that may be leading to this, but the point is… for whatever reasons, these animals can adapt very rapidly to these urban environments.”
What do you think? Can humans observe the evolution of other species in our lifetime?