If you have ever seen birds under a dense tree canopy, finding a specific bird may be more laborious than your eyes. Several species are mysterious, rarely seen or captured on cameras, and the best way to find them is through their phone calls or songs. However, relying on telephones and songs in the natural environment is more than just assessing the existence of species. The most pleasing singing, the noisy ca calls of birds, the sting of insects, and even the strong winds all have valuable ecological information. This valuable ecological information can be obtained by listening to the entire ecosystem.
The sounds of bioacoustics or nature constitute a “soundscape” as a whole. There are thousands of species that make sounds for different reasons, such as finding a mate or warning other competitors to compete for resources. All these species, singing in different tones, together constitute the soundscape. Soundscape ecology is an emerging field that aims to release this ecological information in soundscapes. It is the study of a group of sound-producing species to understand the relationship between species and their habitats. So how do people enter the natural world to understand the relationship between species and their habitats?
As part of my PhD research, I studied the effects of forest restoration on the birds and insects in and around Kanha National Park by studying their sounds. I compared some ecological indicators of vocal animals in many research sites. These sites include forests of diverse species, forests currently being restored and large areas of Lantana camara (Lantana camara), an invasive but ubiquitous bush in India that is related to forest degradation. I have not only studied the differences in the species communities in these places, but also the possible differences in their vocal behavior as a whole.
This research is timely for several reasons. First, large attractive carnivores, especially big cats, have received most attention and protection. For example, recently, insects have experienced a sharp decline worldwide, but the attention of research and conservation circles has been insufficient. Second, unlike deforestation, forest degradation is mysterious, and understanding the effects of slow changes in forests on species is necessary to design and strengthen conservation plans. Finally, it is essential to apply remote sensing technology to research in today’s world. Bioacoustics provides a broad and rapid means to study ecosystems. This technology is usually the first step to monitor the ecosystem, and then conduct more humane investigations and research when needed.
To capture these sounds and study them, I climbed up the tree, sometimes to the end of the branch to connect to my tape recorder. These sturdy tape recorders braved the wind and rain, and often brutally attacked by curious squirrels and garden lizards, capturing all vocal species that shout and sing between 0 and 24,000 Hz. As always, using technology in harsh outdoor conditions with limited resources requires an innovation to protect and maintain equipment. I used a wooden cover as a recorder, which was the idea of Arjun Ramesh, the brother of my initial collaborator. Although AudioMoth recorders are more refined than SWIFT recorders due to the lack of an external metal or plastic casing, they are easier to use due to their weight and compact size. In addition, a zippered bag is sufficient to protect the AudioMoth recorder from bad weather.
The remote sensing technology I use, such as a tape recorder, enables scientists to passively collect data in habitats with minimal human disturbance. This is similar to having a peephole through which you can observe or hear the sounds of species without letting our presence interfere with their behavior. Leave the recorder outside for seven days at a time and let it record continuously during this time. When I finally find the recorder, I always feel surprised. I once heard a group of Hanuman langurs and barking sirens because of the drama happening around them. In some places, I heard a village in the distance wake up and the birds began to sing at dawn like a clockwork. Acoustic data is both a joy and a scientific endeavor. I often find myself imagining and trying to piece together the events that occurred during the collection of sound data.
Ironically, I used a visual aid-Spectrogram to analyze the data I collected. The spectrogram visualizes each species that vocalizes within the sound radius of the recorder. Humans can hear a limited frequency range. Therefore, the spectrogram allows us to visualize the vocalization of all species, even those extremely high and low frequencies that we usually cannot hear. The spectrogram also serves as an image to be analyzed using artificial intelligence (AI).
The biggest advantage of using remote sensing technology for research is the ability to collect large amounts of data. However, to filter the TB acoustic data I collected, it turns out that AI is the most effective method. After manually analyzing a small portion of the data, I can train the AI to find whether there are specific species or specific types of calls in the data. The capabilities and methods of this type of AI provide the tools needed to conduct large-scale research to understand patterns (if any) in the widespread human impact on nature and wildlife. With the continuous development of new technologies, the future of research and conservation looks exciting and has the potential to discover another dimension of the ecosystem and respond to urgent challenges in this field.
Pooja Choksi Currently a doctorate. Candidate of Columbia University in New York, co-founder of the Dhvani project, the Dhvani project is a long-term acoustic monitoring project in India. She studied the impact of forest regeneration and restoration on the fauna of central India.
This series is a project initiated by the Nature Conservation Foundation under its Nature Communication Program to encourage natural content in all Indian languages. If you are interested in writing articles about nature and birds, please fill out this form.
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