Posted by Dr G. Bittar, 2013.11.11
Many highways are embellished with hedges along the roadsides, and also separating the two driving directions. Observant people might wonder how come they are not even more killing fields for animals than they are. The obvious answer is that no bird or animal in its right mind would hang around this noisy hell, where if you’re not hit you die from barotraumatic shock, or from very high pollution. The following study confirms this: birds do avoid these extremely noisy places… because they understand noise is bad for them!
So, perhaps administrations will read this study and finally stop including these road-side areas in their “green areas” statistics. Roadside flowering plants are a pleasure for the eye of the drivers, and contribute efficiently to lower traffic noise, but they are not really an ecological contribution.
Dr G. Bittar
An experimental investigation into the effects of traffic noise on distributions of birds: avoiding the phantom road
McClure et al. 2013
Proceedings of the Royal Society B: Biological Sciences, 2013; 280 (1773)
Abstract
Many authors have suggested that the negative effects of roads on animals are largely owing to traffic noise. Although suggestive, most past studies of the effects of road noise on wildlife were conducted in the presence of the other confounding effects of roads, such as visual disturbance, collisions and chemical pollution among others. We present, to our knowledge, the first study to experimentally apply traffic noise to a roadless area at a landscape scale — thus avoiding the other confounding aspects of roads present in past studies. We replicated the sound of a roadway at intervals —alternating 4 days of noise on with 4 days off— during the autumn migratory period using a 0.5 km array of speakers within an established stopover site in southern Idaho. We conducted daily bird surveys along our ‘Phantom Road’ and in a nearby control site. We document over a one-quarter decline in bird abundance and almost complete avoidance by some species between noise-on and noise-off periods along the phantom road and no such effects at control sites— suggesting that traffic noise is a major driver of effects of roads on populations of animals.
Co-author Barber thus concludes: “Traffic noise is a major driver of the effects of roads on populations of animals.“