In the Valparai plateau of the Anamalai Hills, two researchers stand in a forest fragment and listen carefully. Both work on bioacoustics – studying sounds in a landscape (the soundscape) to know more about life around them.
One of them is straining to discern whether the bird that is making a sharp, cheery call is a yellow-browed bulbul or an Asian fairy-bluebird. In the dense green vegetation around them, there is little hope of seeing the bird, so she must rely on the call to identify the species.
In the meanwhile, the other researcher has just finished his own task. He has put up a small audio recorder in a Ziploc bag, and tied it to the trunk of a Cullenia tree bearing spiky ball-like fruits.
The first researcher carried out a point count of birds, where she simply stood in a spot and took note of the species around her, based mostly on their vocalisations. Data collected this way is used to explore the species diversity in forests and estimate the abundance of birds at small scales. Studies like this are reliant on a high level of expertise, on-the-ground effort and time. Often, such surveys are carried out early in the morning, and nocturnal birds and birds of prey are overlooked.
The second researcher, who placed recorders in the field will enjoy several advantages over the first one’s method. Huge swathes of forests can be covered by placing multiple units simultaneously, and recorders can be programmed to collect data throughout the day, for weeks at a time. This data, free from individual bias, can be reanalysed many times over to answer a variety of questions. If programmed to capture sounds of the appropriate frequency, these recorders can capture bat, frog and insect vocalisations in addition to bird calls.
Read the full story on Mongabay-India here.
Musings from the great outdoors 