Exceptionally Loud Birds: Understanding Avian Sound Amplitude

06 Oct 2026

Tags: Environment   Conservation   Protection frameworks

Source: The Indian Express

Context: A new study has identified the bare-throated bellbird and red-legged seriema, both from Brazil, among the loudest birds recorded.

• Their calls reached around 121–122 decibels (dB), making them louder than several familiar high-intensity sounds such as jackhammers, chainsaws and elephants.
• The study represents one of the largest cross-species comparisons of sound amplitude in birds.

Key Findings of the Study

• The bare-throated bellbird produces extremely loud calls to attract females and can produce sounds exceeding those of elephants, jackhammers and chainsaws.
• The red-legged seriema was found to be another exceptionally loud Brazilian bird, joining the bellbird among the highest-volume species studied.
• Researchers recorded 123 bird amplitudes to create a database for understanding how different species produce such powerful sounds.
• Bird-call amplitudes varied substantially across species; the softest calls, produced by hummingbirds, were around 50 dB, comparable to moderate rainfall.
• The bellbird and seriema produced the highest recorded amplitudes, reaching approximately 121–122 dB.

What is Sound Amplitude?

• Amplitude refers to the height or magnitude of a sound wave and is a major determinant of how loud a sound is perceived.
• Greater amplitude generally corresponds to greater sound intensity/loudness.
• Decibel (dB) is a logarithmic unit used to express the intensity or level of sound.
• Because the decibel scale is logarithmic, an increase in dB represents a much larger increase in sound intensity than the numerical difference alone suggests.

How Did Researchers Measure Birdsong?

• Measuring sound amplitude in the wild is difficult because researchers must distinguish the bird's call from background noise and other birds.
• Researchers used a rangefinder to determine the distance between themselves and the calling bird.
• A sound-level meter was then used to identify the sound level produced by the bird.
• These measurements allowed researchers to account for the effect of distance on recorded sound levels.
• The research was facilitated by the relatively quiet conditions during the COVID-19 pandemic lockdowns, when reduced human activity provided opportunities to record bird calls with less background noise.

Why Are These Birds So Loud?

Bare-throated Bellbird

• The bare-throated bellbird lives in the Atlantic Forest of Brazil.
• It produces a distinctive metallic chirp and uses extremely loud calls in its reproductive communication, particularly to attract females.
• The study highlights the need to understand how its anatomy enables such unusually high-volume vocalisation.

Red-legged Seriema

• The red-legged seriema is about the height of a crane and occurs across Brazil's savannas.
• Its call is amplified by the length of its neck and the shape of its beak, according to the study.
• Unlike the bellbird's metallic call, the seriema produces more elaborate, melancholic vocalisations.

Why Study Extremely Loud Birdsong?

• The researchers aim to understand the evolutionary and anatomical mechanisms that allow some birds to produce exceptionally powerful sounds.
• Comparing species with very different vocalisations can reveal how body structure, behaviour and habitat influence communication.
• The study also provides a broader database for investigating the evolution of birdsong and acoustic communication.

Ecological Significance of Birdsong

• Birdsong plays important roles in mate attraction, territorial communication, species recognition and social interaction.
• The ability to produce louder calls may provide an advantage in environments where sound must travel through dense vegetation or over long distances.
• However, extreme vocalisation also reflects an evolutionary trade-off involving energy expenditure, anatomy and the acoustic characteristics of habitats.