Hi everyone
I hope I can shed some light on this
issue.
On the day I found the owl, there was one
regurgitated pellet on the ground and a few splashes of excreta. The excreta
had a few dark green streaks in it which Jerry Olsen explained was an indication that the bird may have a
gastro-intestinal problem.
This link (http://www.themodernapprentice.com/mutes.htm)
has a heap of info about excreta. About halfway down the page there is a
discussion on diseased mutes. Green or yellow urates can mean a liver disease,
an empty GI tract, or even starvation.
So, the problem has nothing to do with
pellets, or bringing anything up.
Our observations of the owl early on indicated
that it wasn’t eating (no prey items in the feet, little or no excreta or
pellets), however, we found out that gardens staff had cleaned up prey remains
from the garden bed.
Leo’s
observation of the bird eating is very important, and I’d suggest a short
note for Canberra Bird Notes.
Yesterday, I also spoke to the gardens
staff member that was at the owl roost. She was quite unhelpful to the point of
rudeness, and essentially had contempt for anyone there. She was under the
incorrect impression that people observing the bird were keeping it awake all
the time thereby contributing to its poor state of health.
The fact that the stained excreta was
evident on the day the bird was found indicates that its GI condition was
pre-existing and had little to do with it being disturbed at its roost.
Cheers
Anthony
-----Original Message-----
From: David McDonald
[
Sent: Sunday, 17 June 2007 5:46 PM
To:
Subject: RE: [canberrabirds]
Powerful Owl
I do not claim any professional expertise on such matters, but a google
search reveals this at the Audobon Magazine site http://audubonmagazine.org/birds/birds0203.html
:
Take the strange adaptive
changes that occur in the innards of the black-billed cuckoo, a voracious
consumer of forest caterpillars. "Stomach contents of individual cuckoos
may contain more than 100 large caterpillars or several hundred of the smaller
species," writes Janice M. Hughes of Ontario's Lakehead University in her
account of the species. "The bristly spines of hairy caterpillars pierce
the cuckoo's stomach lining, giving it a furry coating. When the mass obstructs
digestion, the entire stomach lining is sloughed off and is regurgitated as a
pellet."
It is also mentioned, again not wrt owls, in a 1906 issue of The Auk.
Perhaps we'll hear more from our owl experts about this? Perhaps it is
perfectly normal for a Powerful Owl to eject part of its stomach lining in the
pellets, once the lining becomes worn or torn by the rough stuff in the
stomach?
David
At 17:17 17/06/2007, you wrote:
I went to the ANBG again this afternoon see the owl with Frank Antram
who was in England when the bird was last seen.
I arrived at the site a little earlier than Frank and saw Stuart Harris in
conversation with a ranger. I felt very uncomfortable when confronted by this
extremely officious person who let it be known to Stuart Harris and I that she
wished people would go away and leave the owl alone. When Stuart explained that
if the owl was concerned by the presence of humans it was unlikely to return to
the same roost site day after day, she informed us that the owl was dying. Her
explanation for this was that pellets had been examined and found
to contain stomach lining and in her words it was ‘shitting it’s
stomach up’. I didn’t bother to explain that pellets are
regurgitated. ..but is anyone able to confirm or deny this story.
Cheers
Alastair
From: Stephen Martin
Sent: Sunday, 17 June 2007 1:29 PM
To:
Subject: [canberrabirds] Powerful
Owl
The Powerful Owl was back roosting in its usual Paperbark tree at the ANBG this
morning.
Stephen Martin
