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.
Philip
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.
