Why can some birds’ calls carry so far?

Jeff Podos and João C. T. Menezes measured the maximum vocal amplitude of 123 bird species. Comparable records were not available for 113 of them. The bare-throated bellbird and red-legged seriema emerged as candidates for especially loud calls.

To compare sounds recorded at different distances, the researchers combined sound-level meters with laser rangefinders. The study reports values standardized to one meter: amplitudes ranged from 64 to 122 decibels across the sampled species. This measurement does not directly equal the loudness a person would perceive in the field.

The team found an association between greater vocal amplitude, larger bodies and wider beak openings. Body structure may help produce or project intense sounds, but the comparison alone does not establish the precise mechanism or show that these traits are the sole cause.

The data did not clearly support hypotheses about weaker flight, dense habitats or mating systems. The work therefore maps relationships between physical traits and amplitude, but it does not yet explain why evolution favored especially loud calls in some species.

Podos and Menezes published the study in Evolution; a University of Massachusetts Amherst news report was written by Daegan Miller. The evidence expands available measurements, but it does not establish a universal record or resolve the ecological function of loud calls.