Tawny Frogmouths

To: 'Martin Butterfield' <>, 'COG List' <>
Subject: Tawny Frogmouths
From: Philip Veerman <>
Date: Thu, 14 Jun 2018 05:50:35 +0000

The words are a bit misleading there in that “about 40 less birds recorded” really means 2 fewer birds recorded (or observed, really), because a species on a site on a year is one record on the GBS database. In this case, comprising many repeat observations over many weeks (not discounting that this is worthy data too). If the GBS system was done daily, Martin’s number could possibly be multiplied by 7 but it is still the same number of birds.


Even so, Martin repeats a well established point that the GBS statistics year by year can be very altered for a species that is limited in range but often repeat sighted at one or a small number of sites.




From: Martin Butterfield [
Sent: Thursday, 14 June, 2018 5:52 AM
To: COG List
Subject: [canberrabirds] Tawny Frogmouths


The pair of Tawny Frogmouths that I used to find every day (apart from Summer) are not using any of their previous roosts at present.  Unless someone else ha had a pair take up residence I suspect the A and F values are going to take a dive in GBS year 37 with at least 20 less observations and about 40 less birds recorded. 


However they are still in the general area with occasional sightings - most recently 5 minutes ago, when one swooped on a moth on my study window.



<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