Thanks Harvey and David. When this comes up I think of Ben King’s (Birds of SE Asia) description of how to measure total length of a
live bird. An extract is as follows.
Note the ‘gently and slowly, without pulling too hard’. [!!! – remember to involve an assistant for egrets and pelicans, maybe for a Great Crested
Grebe even] The reference to a ‘curved neck measurement’ is to a beak-tail measurement with the neck in one of the conceivable curved positions that is perhaps what you might get by applying the scale in the field guide to the bird as illustrated. Applying
the given scale to the raven illustrations in ABG we have an unstretched A Rav of 43.5cm (cf HANZAB 46-53) Little Rav 41.2 (HANZAB 48-52). But did HANZAB ever do any serious stretching – or only make an estimate of stretched length? Length is only included
as a ‘general indication’ of size.
Another way to do it in a popular field guide is as in this US guide, the following indicating size of the Common Poorwill –
From: Perkins, Harvey [
Sent: Friday, 16 June 2017 11:17 AM
To: 'David Rees'; Geoffrey Dabb
Subject: RE: [canberrabirds] Thoughts on the 2 local ravens (3) [SEC=UNOFFICIAL]
David, I think everyone is in agreement on this. The following is what I included in my review that will
shortly be published in CBN…
In contrast to most field guides (as opposed to handbooks), measurements are included for wing length, bill length and weight. These are probably less useful to the average birder than the more typical indication of total body length, whatever
shortcomings that might have.
Harvey
Dr Harvey Perkins
CRC Programme Operations
AusIndustry – Business Services
Phone +61 2 6213 7472
Internet:
business.gov.au
From: David Rees
Sent: Friday, 16 June 2017 11:06 AM
To: Geoffrey Dabb <>
Cc: <> <m("canberrabirds.org.au","canberrabirds");">>
Subject: Re: [canberrabirds] Thoughts on the 2 local ravens (3)
The point you make about lack of 'bird-length' is in my view one of the deficiencies of the new CSIRO field guide. While the wing, beak etc. measurements are absolute data, however, they are of little use on their own to an 'observer'.
Most customers of this field guide will be observers. Case of 'purity' over 'practicality' here.
The new book seems to me to be a close copy of the format used by Svensson
et al (1999) in their European field guide, first published in Sweden, but probably better known to readers in its English language edition published by Collins as the 'Bird Guide ......" It seems a pity to me that CSIRO Publishing did not follow the
size format used for that book, which is far more compact and field friendly. See what I mean in photo enclosed
That said, the artwork in the new field guide is magnificent, and probably the best out there from anywhere and the artists and authors should be congratulated for that.
On Sun, Jun 11, 2017 at 3:16 PM, Geoffrey Dabb <> wrote:
Bird length is not a straightforward matter. Most field guides give it as offering some kind of help in appreciating size. The Australian Bird Guide departs from that practice,
giving instead wing, bill length and weight (these generally taken from HANZAB). Among the reasons for not giving length: ‘the measurement [is] typically taken from dead specimens stretched into positions that are never assumed in life. Trying to reconcile
the total lengths presented in books with those observed in the field can therefore be confusing.’ (ABG does offer a scale on the illustration pages.) HANZAB does not give tabulated lengths in the Plumages section but does provide length in the field identification
section ‘in gross terms, as a guide to the size of the bird’.
Bearing in mind that warning, the following given ‘lengths’ (cms) might be noted:
Aust Raven: HANZAB 46-53; Pizzey 48-52
Little Raven: HANZAB 48-52; Pizzey 48-50
From weights and other size info in HANZAB it is clear that males are larger than females so a female A Rav might be no bigger than (or even smaller than) an individual Little Raven.
Relative sizes might only be an issue if you see both species together – and particularly if you are counting species. The below is a selection of snaps from Trucking Yard Lane
last week when a single A Rav was squabbling with 4-5 Little Ravens at the remains of a deceased duck. You can correct my tentative labelling, if you like.
