Re: Birds' eyes

To: Shane Raidal <>
Subject: Re: Birds' eyes
From: James Davis <>
Date: Fri, 27 Mar 1998 16:33:58 +1000 (EST)
Shane: Has anyone identified any function for "hippus"?  Why only parrots?
Cheers, Jim

Dr. Wm. James Davis

> The regular fast opening and closing of the iris is called "hippus" and the
> best example of this in Aus birds that I can recall is the rainbow lorikeet
> but most lorikeets and other psittacine birds display hippus.  Unlike
> mammals the avian iris contains striated muscle which means they have more
> "control" over the pupil diameter.  They can probably alter the pupil much
> in the same way we wink.  

<Prev in Thread] Current Thread [Next in Thread>

The University of NSW School of Computer and Engineering takes no responsibility for the contents of this archive. It is purely a compilation of material sent by many people to the birding-aus mailing list. It has not been checked for accuracy nor its content verified in any way. If you wish to get material removed from the archive or have other queries about the archive e-mail Andrew Taylor at this address: andrewt@cse.unsw.EDU.AU