OTTAWA, Canada - Birds can sense posted speed limits on roads and react to avoid flying into vehicles, according to a study out Wednesday.A researcher says birds seemed to have adapted to average vehicle speeds as a feature of their environment, such as the risk of avian predators. Pierre Legagneux, a behavioural ecologist at the University of Quebec, told AFP that strict enforcement of speed limits could significantly help with conservation, especially for endangered species, in suburban areas, Legagneux said: "I realised the birds were not reacting to the actual speed of my car but to the average speed of cars on these roads, to the posted speed limits. The birds associate road sections with speeds as a way to assess collision risk so strictly enforcing speed limits could reduce the frequency of the collisions with vehicles."BIRD TIMINGThe study was published in the Royal Society's journal Biology Letters.The researcher said he was tracking ducks in western France for another project when he came across a bird on a road that forced him to stop and caused him to wonder how birds thought about cars and how they avoided them.He began studying bird responses from November 2006 through November 2007 during his commute to and from his laboratory through farmland, forests and villages .With colleague Simon Ducatez, he monitored and analysed the responses of 21 species of bird on roads with speed limits of 20, 50, 90 and 110km/h. The process involved noting when a bird took off to avoid his approaching car and how long it took the bird to reach its final position on the ground.