Conversational Noise Reduction to Benefit Amazon Birds

For all its positive attributes, the recent expansion of ecotourism has resulted in greater influxes of people into natural areas, causing a range of impacts including behavioral disruptions among wildlife.

How animals respond to conversation is poorly understood, but noise reduction may reduce the impact of ecotourists while simultaneously enhancing their experience with higher wildlife encounter rates.

We tested the response of a rain forest bird community to noise by playing a recorded conversation while conducting point censuses in a terra firme forest in Tambopata, Peru.
  • Fifty decibel conversation (approximately library speaking volume) caused declines of 35 percent in total detections and 33 percent in detected species richness.
  • Birds reacted similarly to 60 dB (approximately the volume of an excited child):
  • Average detections declined by 39 percent and detected species richness by 37 percent.
  • Specifically, noise-induced detection declines were manifest both in decreased vocalizations (37% decline) and decreased physical sightings (44% decline).
Lowered detection frequencies indicate behavioral shifts. As vocalization is involved in territory defense, breeding behavior, and predator detection, strong noise responsiveness indicates potential harm for birds. Insectivores were the most affected bird guild, raising conservation concerns, as insectivorous birds are sensitive to habitat modification. Birds reacted strongly to noise both near an established ecotourist lodge and in an intact reserve, indicating an absence of habituation. Thus, as a method for reducing ecotourismís footprint on native fauna and improving tourist satisfaction with increased wildlife sightings, noise reduction seems promising, even for well-established ecotourist lodges.