points of identification

To: Birding Aus <>
Subject: points of identification
From: Laurie&Leanne Knight <>
Date: Wed, 20 Mar 2002 21:14:53 +1000
The following item from the New York Times -
March 9, 2002
Will Fingerprinting Stand Up in Court?

- got me thinking about the issue of bird identification.

Basically, the issue is that the validity of fingerprint analysis in the US
justice system has come into question.  While finger prints are unique to
individuals, the issue is the way prints are "read and matched".

The question in practice is "how much of a match is required to say that a
particular fingerprint is from a particular person."  Apparently, the process
used to match "large, evenly pressured prints taken from suspects at the police
station to 
smaller, unevenly pressured prints from crime scenes  is ultimately 
subjective and bedeviled by inconsistent standards. The French, for 
example, require that two fingerprints match at 16 points before they can 
be accepted as coming from the same person; the Australians, 12; and the 
Swedes, 7. The F.B.I. refuses to state a number at all, relying instead on 
case- by-case judgments."

A judge has also noted ""alarmingly high" error rates when fingerprint examiners
took proficiency tests; in 1995 only 44 percent of 156 law enforcement examiners
could correctly identify all five prints in the test, and in a 1998 study the
number improved to only 58 percent."

Perceptive readers will by now see a connection between the fingerprint analysis
and the identification of problematic species [eg waders in non-breeding 

First, it is easy to compare a bird "in the hand" with a description in a field
guide.  It is another thing to positively ID a partially sighted bird moving
about in the distance through a foggy magnifying instrument in poor light.

Second, how many points of identification do you need for a rare species to get
onto the rare bird sighting list? 

Generally, when we observe birds, we take shortcuts - for example, one or two
seconds of a call, or a flash of white to list a pied currawong.  Often there is
just one point of identification we look for [eg the yellow patch on the side of
the fact to ID a lewin's honeyeater].  While these single points are good rules
of thumb, we may sometimes get caught out with the assumptions me make.

I would think there is a degree of subjectivity in the judging of rare bird
sightings [as evidenced in some of the recent discussions about rare migrants on
BOz] and it would be interesting to know [if one was a "recording angel] the
frequency of type I and type II errors in the annals of rare bird recordings [ie
false positives and false negatives].

As a partially related aside, as I was lugging the week's shopping home up a
long hill round dusk this evening, I heard the characteristic clucking of one of
the local tawny frogmouths.  I looked in the direction of the call, and saw a
bush turkey settling in for the night on a tree branch.  A humourous 

Birding-Aus is on the Web at
To unsubscribe from this mailing list, send the message
"unsubscribe birding-aus" (no quotes, no Subject line)

<Prev in Thread] Current Thread [Next in Thread>
  • points of identification, Laurie&Leanne Knight <=

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