One paper suggests that the damage to mammal eyes is only temporary - it
essentially dazzles the creature as it would you or me. This is bad news for
prey species which are then more susceptible to predation for approximately 20
minutes or so. If you think about it, these animals are fine in sunlight -
although I haven't seen the paper mentioned earlier which talks about permanent
damage for nocturnal species.
In any case, the red lens over the front is generally accepted as the most
ethically correct way to spotlight nocturnal wildlife.
Chris.
________________________________
From: Chris Sanderson <>
To: ninderry <>
Cc:
Sent: Sunday, 20 September, 2009 11:15:18 PM
Subject: Re: [Birding-Aus] LED light
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
> ===============================
> www.birding-aus.org
> birding-aus.blogspot.com
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