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Brown Goshawk vs Collared Sparrowhawk identification

To: "Messages Birding-aus" <>
Subject: Brown Goshawk vs Collared Sparrowhawk identification
From: "Bob Forsyth" <>
Date: Fri, 4 May 2001 12:42:21 +1000
G'day all,
 
Refer my posting of 2/05/2001 about my  " identification comparison chart "
 
Michael Norris has kindly advised me of a paper in
BOCA's "The Australian Bird Watcher"
 
The Collared Sparrowhawk  A Review and Comparison with the Brown Goshawk.
Czechura, Debus, Mooney
Vol. 12, No. 2, June 1987 ,pages 35 - 62
 
This paper should be read by all who want to more confidently identify the two birds.
 
Here are some extracts...
... " While the difference in tail shape is real and important, our field experience and check of museum spesimens suggest that some qualification is required. "
 
They continue...
... " since a tail which is square when folded is often rounded when fanned "
... " Feather disarray, moult or abrasion can affect tail shape "
... " We suggest that other characters (e.g. silhouette, flight pattern) be used to supplement field identification, and that observers be aware of exceptions to the general rule. "
 
An interesting note is
... " The main distinguisher field character, tail shape, has been common knowledge only since 1970 (Slater 1970) "
 
This would mean that observations before this date would have to be suspect ?
 
My table is an attempt to summarise some other identifying features, in a simple form for the non specialist observer.
 
Regards, Bob Forsyth, Mount Isa, NW Qld.
 
 
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