Birds apparently take speed limits into account to avoid being hit by oncoming traffic as they forage near roads.
On a drive home from the laboratory, researchers in Canada conducted a straightforward experiment: They traveled stretches of road with various speed limits and tested how close a bird on or beside the road would allow the advancing car to come before fleeing its dangerous position, a measure called flight initiation distance.
As soon as the scientists saw a bird fly away, they started a timer and recorded how long it took them to reach the spot where the bird had been. They ran the experiment at different speeds — at, above and below the legal limits. When they calculated the distance at which birds bailed for safer ground, they found that this distance was greater on roads with higher speed limits.