Hiking quietly benefits birds... and birders

Credit, Or Hiltch.Ecotourism has become a major strategy in conservation.  The hope is that the financial benefits of bringing tourists to see native plants and animals in their natural environs raises local interest in protecting those environs.  Tourists enjoy seeing birds and other animals engaged in their daily activities, and ideally those birds and animals are more assured of having intact habitat.

Recent research has uncovered a downside to this arrangement, however, one that should be familiar to anyone who has taken a wilderness walk with a child:  Human voices tend to scare off the very wildlife we are interested in seeing. 

Daniel Karp and Roger Guevara played recordings of human voices along transects through high density bird community habitat around Refugio Amazonas, an ecotourism lodge in southern Peru.  Censuses of birds were taken following the broadcasts, by aural and visual counts. 

Detection counts of birds along the transects after the recordings were played decreased by as much as 37%.  This was true both in locations frequently visited by tourists and in remote locations where humans are rarely seen.

A decline in animal sightings has the potential to reduce interest in ecotourism activities, eroding support for environmental protection.  It also means that the birds’ typical behavior patterns are being disrupted. 

The reduction in bird calls and sightings is likely the result of those individuals adopting predator responses that render them less visible.  This time spent hiding from potential danger may mean less time spent foraging, defending territory and attracting a mate, all to the detriment of the birds’ overall health.

The researchers found no evidence that birds might be becoming habituated to human voices.  The decrease in census numbers following broadcasts of human voices was the same in locations where birds were likely to encounter people on a regular basis as in locations where avian-human interactions are infrequent. 

If birds were becoming habituated to human voices, one would expect the decrease in census numbers to be smaller in higher traffic areas.

Fortunately, this is a problem with a fairly easy solution.  Operators of ecotourism resorts and wildlife tour guides can promote a silent approach to wildlife viewing.  Benefits will accrue to both humans and animals – tourists are more likely to see the species they are interested in, and those species are less likely to have their typical behaviors disrupted.

The adage “take only pictures, leave only footprints” can now be amended to include “hear only animal calls.”

--Karren Bassler is a contributing writer based in Madison Wisconsin and a consultant with Superior Nonprofits, LLC.

Karp, D., & Guevara, R. (2010). Conversational Noise Reduction as a Win-Win for Ecotourists and Rain Forest Birds in Peru Biotropica DOI: 10.1111/j.1744-7429.2010.00660.x