WE TOOK a drive along the East Coast road the other day – and almost killed a hapless pigeon. It came out of nowhere, as they do, flashed across the windscreen in the blink of an eye, followed the road alongside us for a few seconds and then disappeared over a high hedge.
“Lucky bird,” muttered the beloved. “We actually hit him – or at least he hit us.”
“Really,” I responded, rather sceptically. “I thought it got away unscathed; it looked to me as if it floated across the windscreen on a cushion of air.”
“It did,” replied he-who-hates-to-be-wrong, “but it definitely hit something first.”
He was right (this time). It had collided with our aerial – one of those telescopic ones you pull up from the side of the windscreen – and snapped it clean off.
Back home, I logged onto the internet to see if I could find an estimate for the number of birds killed on SA’s roads each year. I couldn’t, but I did come across a horrifying statistic for the USA. According to sciencedirect.com, 80-million birds end up as road-kill every year. Sounds ridiculous but it’s quoted in all sorts of other places, too, so who knows? I hate to think what the number is worldwide, or how many have been killed since motoring started. In 1920, according to the University of California, American naturalist Joseph Grinnell noted: “This is a relatively new source of fatality, and if one were to estimate the entire mileage of such roads in the state, the mortality must mount into the hundreds and perhaps thousands every 24 hours.”
I’m delighted to report that avian road deaths are definitely on the wane these days, according to US researchers. Too slowly, to my mind, but there’s a definite shift in the right direction – and it’s all down to evolution.
Husband-and-wife team Charles R Brown and Mary Bomberger Brown of Tulsa University published a paper called “Where has all the road-kill gone?”. (I bet their parents never dreamt that’s what they’d end up studying!) Their findings, based on a 30-year study of Petrochelidon pyrrhonota killed by cars in southwestern Nebraska – cliff swallows, to you and me – show the number has shrunk significantly.
The researchers found swallows killed by cars generally had a larger wingspan than others in the colony, reports Die Welt, so they’d have had a tougher time avoiding oncoming cars; those with shorter wingspans could turn away more quickly.
“One possible explanation is that selection has favoured individuals whose wing morphology allows for better escape. Since they don’t die as frequently in collisions, they have more reproductive success than longer-winged swallows.”
In other words, they’re evolving into shorter-winged creatures to suit the circumstances.
It is, says John Hoogland, an evolutionary biologist with the University of Maryland’s Centre for Environmental Science, “a beautiful trend that never could have been predicted”.
Our pigeon’s escape was just good luck, we thought – but, then again, who knows?
Today’s Chiel is Stevie Godson. E-mail her at
The evolution of road-kill
“Lucky bird,” muttered the beloved. “We actually hit him – or at least he hit us.”
“Really,” I responded, rather sceptically. “I thought it got away unscathed; it looked to me as if it floated across the windscreen on a cushion of air.”
“It did,” replied he-who-hates-to-be-wrong, “but it definitely hit something first.”
He was right (this time). It had collided with our aerial – one of those telescopic ones you pull up from the side of the windscreen – and snapped it clean off.
Back home, I logged onto the internet to see if I could find an estimate for the number of birds killed on SA’s roads each year. I couldn’t, but I did come across a horrifying statistic for the USA. According to sciencedirect.com, 80-million birds end up as road-kill every year. Sounds ridiculous but it’s quoted in all sorts of other places, too, so who knows? I hate to think what the number is worldwide, or how many have been killed since motoring started. In 1920, according to the University of California, American naturalist Joseph Grinnell noted: “This is a relatively new source of fatality, and if one were to estimate the entire mileage of such roads in the state, the mortality must mount into the hundreds and perhaps thousands every 24 hours.”
I’m delighted to report that avian road deaths are definitely on the wane these days, according to US researchers. Too slowly, to my mind, but there’s a definite shift in the right direction – and it’s all down to evolution.
Husband-and-wife team Charles R Brown and Mary Bomberger Brown of Tulsa University published a paper called “Where has all the road-kill gone?”. (I bet their parents never dreamt that’s what they’d end up studying!) Their findings, based on a 30-year study of Petrochelidon pyrrhonota killed by cars in southwestern Nebraska – cliff swallows, to you and me – show the number has shrunk significantly.
The researchers found swallows killed by cars generally had a larger wingspan than others in the colony, reports Die Welt, so they’d have had a tougher time avoiding oncoming cars; those with shorter wingspans could turn away more quickly.
“One possible explanation is that selection has favoured individuals whose wing morphology allows for better escape. Since they don’t die as frequently in collisions, they have more reproductive success than longer-winged swallows.”
In other words, they’re evolving into shorter-winged creatures to suit the circumstances.
It is, says John Hoogland, an evolutionary biologist with the University of Maryland’s Centre for Environmental Science, “a beautiful trend that never could have been predicted”.
Our pigeon’s escape was just good luck, we thought – but, then again, who knows?
Today’s Chiel is Stevie Godson. E-mail her at
Would you like to comment on this article?
Register (it's quick and free) or sign in now.
Please read our Comment Policy before commenting.
Trending Now
Latest Videos