To: "Geoffrey Dabb" <>
Subject: currawongs
From: "martin butterfield" <>
Date: Mon, 17 Mar 2008 11:06:33 +1100
The main thing that can be said about the long term trend for Pied
Currawong abundance in the GBS results is that there is no trend.  The
values of the correlation coefficients for linear and polynomial
trends for 21 and 26 year results for the species range from just over
0.1 to nearly 0.3.  These are well below the values that would
indicate a trend significantly different to zero.

I have attached a graph showing A values by week (months are difficult
since the weeks don't all start and finish at the bginning/end of
months) for 21 years and later years.  This clearly shows a flattening
of the seasonal distribution in the recent past with more birds in the
warmer months and less in the colder months.  There has been previous
correspondence on this list (last year some time) about the reduced
frequency of the huge flocks seen (particularly in the Weston area) in
the early years of the Survey.


Attachment: Pied Currawong graph.doc
Description: MS-Word document

This is the email announcement and discussion list of the Canberra 
Ornithologists Group.
List-Post: <>
List-Help: <>
List-Unsubscribe: <>
List-Subscribe: <>
List archive: <>
List manager: David McDonald, email 
<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 Canberra Ornithologists Group 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 list contact David McDonald, list manager, phone (02) 6231 8904 or email . If you can not contact David McDonald e-mail Andrew Taylor at this address: andrewt@cse.unsw.EDU.AU