Fieldwork Reveals 123 Bird Species Amplitude Data
Biologists Jeffrey Podos and João C.T. Menezes published a study on September 29, 2026, in the journal Evolution, revealing amplitude measurements across 123 bird species after conducting fieldwork in Amherst, Massachusetts, and across Brazil. The research catalogs call volumes for 113 species that had never been measured previously, establishing a 58-decibel range spanning from quiet hummingbird calls to extreme peaks exceeding 120 decibels.
Measuring bird calls in natural environments has historically presented distinct technical obstacles. Sound amplitude naturally attenuates over distance, making recordings taken near a microphone vastly different from the actual output volume at the source. While controlled laboratory testing of captured specimens bypasses this distortion, such methods remain impractical for large-scale international comparisons.
Podos and Menezes overcame this field limitation by adopting non-traditional hardware. They utilized accurate laser rangefinders originally developed for golf alongside portable, high-resolution sound meters built for workplace safety monitoring. Combining these instruments allowed the researchers to simultaneously calculate precise distances and record sound pressure levels directly in the wild.
Decibel Range Spans From Hummingbirds to Bellbirds
The collected data exposed vast disparities in vocal output across avian species. At the lower end of the measured spectrum, a hummingbird registered approximately 64 decibels, a level roughly equivalent to a standard human conversation. At the upper extreme, the bare-throated bellbird and the red-legged seriema both climbed past 120 peak decibels.
These measurements place both species as direct contenders for the title of the world’s loudest bird. In 2019, Podos documented that the Amazon’s white bellbird produced a call surpassing the volume of a revving chainsaw, a record later validated by Guinness World Records.
| Species | Measured Peak Volume | Comparable Sound Level |
|---|---|---|
| Hummingbird | 64 decibels | Normal conversation |
| Bare-throated bellbird | Over 120 decibels | Jackhammer or chainsaw |
| Red-legged seriema | Over 120 decibels | Jackhammer or chainsaw |
The new measurements expand the foundational dataset available to ornithologists studying acoustic communication. Podos noted that conducting this scale of field research points toward numerous subsequent inquiries.
Physical Anatomy Drives Extreme Volume
Analyzing the physical traits of the measured birds provided concrete answers regarding how extreme vocalizations are generated. Larger body sizes correlated directly with higher volumes, a dynamic driven by bulkier muscles capable of compressing and expelling larger volumes of air with greater force.
Wider beak openings also accompanied louder calls. This physical adaptation functions similarly to the broad bell of a trumpet, which helps project sound waves outward into the surrounding environment.
However, the underlying evolutionary drivers remain undetermined. Podos and Menezes tested several ecological hypotheses, predicting that exceptionally loud calls would correlate with weak flight capabilities, habitation in dense forests where visual signaling fails, or polygamous mating systems where long-range calls provide an advantage in reaching potential partners.
Unresolved Evolutionary Questions
The empirical data failed to support those initial ecological predictions. While the physical mechanics of body size and beak width successfully explain the how of extreme avian volume, the specific evolutionary whys remain elusive.
Menezes explained that teasing out the ecological factors driving these traits will require expanded datasets encompassing significantly more species. The researchers intend to continue field expeditions utilizing laser rangefinders and sound meters to gather additional observational data.
