Birds in Nebraska, USA, specifically the Petrochelidon pyrrhonota known as cliff swallows to us common folk have evolved shorter wings, which might help them take off quicker avoiding moving traffic.
Charles Brown, a professor at the University of Tulsam, Oklahoma has been picking up dead swallows for about three decades. He states that roadkill figures have declined over the past 30 years, coincidentally the number of roadside nests of these these sparrow-sized birds with orange rumps and white foreheads have risen. The birds killed by traffic have longer wings than birds caught in mist nets for research, and on average the caught birds’ wings have got shorter.
Brown mentioned that after a particularly cold May in 1996, about half the nesting population died through starvation, birds with shorter wings were better able to capture and feed on insects than those with longer wings; so traffic might not be the sole cause.
