It has been quite evidently reported that birds and animals are losing their habitats at a rate which is excessively proceeding. Owing to this, its quite easy to find animals in your locality, colony or on the roads of your city. We should no longer be surprised to find a bear knocking at our door for some shelter and a beer. But, of all these incidents, it has been frequently observed to find some birds nest their homes near the roads.
Roadside habitats are primarily important for a range of taxa including plants, insects, mammals, and birds. Such behaviour is particularly dominant in developed countries in which large area of forest and vegetation have been cleared for agricultural practices and urban development. The roadside vegetation while providing suitable habitat for some species, also exposes them to high levels of traffic noise, visual disturbances from passing vehicles, and the risk of collision with cars and trucks.
Birds have a specific way of interacting with other members. They do so with the help of acoustic signals assigned for various stimulations and alerts. They use these signals for marking territories, attracting mates, scolding members of same or even different species. The increase in traffic noises can significantly reduce the distance over which these acoustic signals can be detected, an effect known as acoustic interference or masking. Studies show that the singing behavior of birds changes in the presence of traffic noise. In a research, the impact of traffic noise and traffic volume on two species of birds was investigated, the Grey Shrike-thrush (Colluricincla harmonica) and the Grey Fantail (Rhipidura fuliginosa), at 58 different roadside sites on the Mornington Peninsula, southeastern Australia.
The results established a difference of varying traffic noise in both the species. The lower singing Grey Shrike-thrush sang at a higher frequency in the presence of traffic noise, with a predicted increase in dominant frequency of 5.8 Hz/dB of traffic noise, and a total effect size of 209 Hz. The higher singing Grey Fantail, however, did not appear to change its song in traffic noise. Also, the probability of finding each species at a specific habitat declined with increase in traffic noise. Conclusively, traffic noise could hamper detection of song by the other members, thus making it difficult for birds to establish connections within their territory and habitat.
The anthropogenic interference of the most advanced species with the other species has led to a habitat that is shrinking and becoming more and more specific, instead of being fit for all species. We need to acknowledge the importance of each species and act accordingly. Remember, coexistence is the most efficient and stable asset that nature has provided us with.