Dimorphism and discrimination between gibbon and siamang vox is
possible, Marc. Also, depending on detailed and calibrated tetrahedral
recording gear, geological and other landscape metadata, some
information on distance and direction is also possible. Stereo
recording data would yield guesses that might verge on "wild." Then
it takes some really good audio forensic software and a grasp of how
sound transmits through different media. When all those elements
converge, some conclusions are possible. We've done some of that.
Bernie
On Dec 16, 2008, at 4:51 PM, Marc Myers wrote:
> Anyone have experience locating animals by measuring distance and
> direction of their calls in natural environments? Gibbons often live
> in difficult terrain, at low densities and in small family groups.
> They can be hard to see in their native environment and are
> critically endangered through the majority of their range. Making
> population estimates is important in conservation planning, when
> advising local governments on forestry use and establishing risks to
> extinction. Gibbons have famously loud and expressive calls,
> typically sounded first thing in the morning. Populations are
> presently estimated based on the frequency, direction and apparent
> distance of the calls. Of course even experienced listeners are not
> very good at estimating distance and as a consequence population
> estimates vary wildly from environment to environment and researcher
> to researcher. Any thoughts?
>
>
>
>
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