Smithsonian Magazine · People & society

South American Birds Among Loudest Known Avians

New research has identified two South American bird species, the bare-throated bellbird and the red-legged seriema, capable of producing vocalizations exceeding 120 decibels, rivaling the sound of a jackhammer. This finding places them among the loudest birds discovered globally.

Scientists utilized recent technological advancements, including laser rangefinders and sound level meters, to accurately measure vocal amplitude in various bird species. This allowed for the isolation and recording of individual bird calls, even in noisy environments.

The study, which collected amplitude data on 123 species, significantly expanded the understanding of bird vocalization volumes. Previously, amplitude data was available for only ten species, highlighting a substantial gap in scientific knowledge.

The research documented a wide range of bird song volumes, from the quiet 64-decibel hum of the dusky-throated hermit hummingbird to the extreme loudness of the bare-throated bellbird and red-legged seriema.

Anatomical comparisons revealed a correlation between larger body size, wider mouth openings, and louder vocalizations, likely due to stronger muscles and more efficient sound radiation.

The evolutionary reasons behind these extremely loud calls remain unclear. While hypotheses suggest mate attraction or communication through dense vegetation, these explanations do not fit the red-legged seriema, which inhabits open areas and is monogamous.

Defining the "loudest bird" can vary based on measurement methods, with different species leading when considering individual calls, averaged loudest calls, or averaged peak volumes.

The amplitude data has potential conservation implications, aiding in species detection, population estimation, and understanding how birds might adapt to environmental changes.

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