Sorry for coming in late on this one. I was visiting some relatives
who live in the wet tropics last week. We did a bit of spotlighting,
looking for Large-tailed Nightjars at dusk with a red lens cover over
the light. We saw a few in flight and picked up their eyes as they
perched in distant trees.
My cousin was of the opinion that many animals don't see so well at
the red end of the spectrum. He backed up this assertion by later
bagging a large boar that we had seen fossicking about his property
(he had the spotlight fixed to the top of the scope of his rifle). He
said he could get a lot closer to the pigs with the red lens cover
than he could if he were using a white light. I had a look at the
beast the next morning - it appeared to be about 1.4 metres long and
had a nasty pair of tusks.
Regards, Laurie.
On 20/09/2009, at 11:15 PM, Chris Sanderson wrote:
Hi Greg,
There's been a bit of info posted in the archives on this before.
Dr Jack
Pettigrew at UQ has done some research on both nocturnal mammal and
bird
eyes and has suggested while bird eyes are more sensitive to low light
conditions, they are also more robust than human eyes. Light in
their eyes
can interfere with feeding behaviour, though I'm not sure how much
of an
impact it has. Nocturnal mammals on the other hand are susceptible to
retinal damage, and this has been seen in some individuals in the
Atherton
Tablelands that were on regular spotlighting tour routes a while
ago. One
suggestion is to use a red filter (or red cellophane) over the front
of the
torch, which helps avoid the eye damage. Combine this with a
technique of
shining the light only briefly onto the animal and try and keep the
main
beam away from the face once you've confirmed an ID.
In terms of eyeshine, LED light does produce a shine, but as you
suspect,
its not as great as standard halogen lights (in my experience at
least).
Regards,
Chris
On Sun, Sep 20, 2009 at 5:01 PM, ninderry <>
wrote:
I recently acquired a LED Lenser 14 flashlight to supplement by
spotlighting
gear, thinking to use it essentially as a camping torch, and was
surprised
at how powerful the beam is. The range and brightness of the beam
rivals my
battery spotlight. I was wondering if anyone has experience with
these Led
Lensers with spotlighting. It's a very white light and the
instructions
include grave warnings about shining it into the eyes of people, so
I was
wondering if there was any reason to think the light might damage
the eyes
of nocturnal critters. Also, I'm not sure if the light will reflect
eyeshine
as well as the standard gear. Any suggestions?
Greg Roberts
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