birding-aus

Re: BIRDING-AUS Kookaburras

To:
Subject: Re: BIRDING-AUS Kookaburras
From: Peter Woodall <>
Date: Thu, 31 Aug 2000 10:29:48 +1000
John Gamblin wrote in response to the posting about Kooks

 
>Very small stones ( before Tony says Mick Jagger ) are
>also found within their bodies? it is believed it
>helps with food digestion? I'd like to hear more from
>our good and very learned friends of this list about
>that?
>They could be attempting to break the stones to use
>for another purpose? keep watching and give them all
>my love please, my laughing friends.
>
>Keep smiling,
>
>John A. Gamblin.
>
>
Birds don't have teeth and so can't chew their food
as mammals do.  So those birds that feed on hard foods,
like seeds, also swallow small stones which lodge in 
their very muscular stomach (gizzard).  As the muscles
of the gizzard contract, the stones are rubbed against
the seeds and so wear down their outer coats, releasing
the starches and oils inside.  This is why poultry are
fed grit as well as the seeds and grains in their food.

Generally carnivorous birds have a much less muscular
gizzard and much less (if any) need of grit in their
diet.  They rely on strong digestive enzymes for digesting
the food.  So I would doubt if the Kookaburra has much
need of grit in its diet, and certainly not stones 45mm
in diameter.

John's suggestion of a muscial (?) link is much more likely.
Perhaps the kooks are trying to hide the stones under the
boardwalk, out of the sun, ......., [and then laugh at the
ensuing activity].

Cheers

Pete
Dr Peter Woodall                          email = 
Division of Vet Pathology & Anatomy             
School of Veterinary Science.             Phone = +61 7 3365 2300
The University of Queensland              Fax   = +61 7 3365 1355
Brisbane, Qld, Australia 4072             WWW  = http://www.uq.edu.au/~anpwooda
"hamba phezulu" (= "go higher" in isiZulu)





                                                             


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