London - When it comes to speed limits, motorists are not the only ones to observe the rules. Birds also change their behaviour according to the maximum permitted speed on a road.

Scientists found birds sitting on roads take off sooner to avoid oncoming traffic on roads with higher speed limits – regardless of how fast the car is actually travelling towards them.

The findings suggest birds adapt their behaviour to the specific characteristics of an area, in this case a road’s speed limit, rather than reacting to the distance and speed of a vehicle.

“As road traffic directly causes mortality in birds, we expect birds to respond to road traffic in a similar way as they would respond to predation,” said the researchers from Laval University in Canada.

“As road mortality probably increases with speed limits we would expect individuals to adjust their anti-predator behaviour to vehicle speed and/or to the speed limit.”

The scientists drove a Peugeot through rural France and recorded “flight initiation distance” (FID) – the closest distance the car came before birds flew away. They wrote in the Royal Society journal Biology Letters: “Birds had significantly higher FID on road sections with higher speed limits. By contrast, car speed had no significant effect on FID.” - Daily Mail