Eye Shine and Owlet Nightjars

Subject: Eye Shine and Owlet Nightjars
From: Andrew Hobbs <>
Date: Mon, 18 Nov 2013 19:57:52 +0800
On 18/11/2013 3:23 PM, Peter Shute wrote:
So Owlet-nightjars don't have this Tapetum Lucidum?
I don't know about Owlet-nightjars. The fainter red colour would suggest not, (Although some animals have a Tapetum Lucidum layer that gives a bright reddish shine) but that seems a bit strange in a bird that is supposed to be nocturnal. Perhaps most of its activity is crepuscular, and there has been less selective pressure to develop or maintain the structure. Alternatively perhaps the evolutionary line lost or didn't gain the ability to produce the structure in the past. The Owlet-nightjars are a group which appears to have evolved rather early on in the evolutionary history of birds. They are certainly not closely related to the owls or nightjars; groups which do appear to have a Tapetum Lucidum layer.

Phylogeny of the owlet-nightjars (Aves: Aegothelidae) based on mitochondrial DNA sequence
John P. Dumbacher, Thane K. Pratt, and Robert C. Fleischer
Molecular Phylogenetics and Evolution 29 (2003) 540–549


I assume putting the torch closer to your eyes to help see the fainter shine 
uses the same principal as moving a camera flash further from the lens to 
reduce red-eye.

Peter Shute

Sent from my iPad

On 18 Nov 2013, at 4:55 pm, "Andrew Hobbs" <> wrote:

The colour of the eye reflection from the Tapetum Lucidum depends upon
the properties of the crystals in the layer.  It can vary more or less
across the full visible spectrum.  However in animals without that layer
the reflection is always red.  The red colour is mainly due to the
haemoglobin in the blood vessels at the back of the eye. (This is the
basis for the red eye effect in people. We don't have a Tapetum Lucidum.

Andrew Hobbs



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