Counting C Myna in GBS: the real story.

To: "'Duncan McCaskill'" <>, "'Paul T.'" <>
Subject: Counting C Myna in GBS: the real story.
From: "Philip Veerman" <>
Date: Tue, 4 Jun 2013 22:53:54 +1000
Duncan is right on current arrangements but I will add this history. Actually the rules of the first 2 versions of the chart were ambiguous, because they said to only record birds dependent on the area. They certainly did not ever mention the word "use". Then they gave some examples but that still left the interpretation vague because it still begged the question about what other behaviours were or were not "dependent". Then it also said but if the birds are not dependent then record them anyway but underline the record. But several categories of records were to be underlined, such as "seen beyond 100 metres". Thus it became completely confusing, with some people routinely underlining some observations and most never did. When the numbers were input to the original computer system, different people doing the input were inconsistent as to which numbers were used. I know because I spent years proof reading all those hundreds of charts as I converted the data into the MS Access system. And in that original system, once a number was entered, it was impossible to change it, without deleting the full record and reinputting the entire line. This is all explained in great clarity in The GBS Report with exact transcripts of the instructions from each chart version and a full description of why the changes were made. It did all this work for a reason, so that discussions like this would not need to happen. I really shouldn't be giving out free extracts of the GBS Report all the time but seeing as the third edition is almost sold out, here is the relevant extract:

Version one of the chart was issued about June 1981. It was used for Years 1 to 6. The design was basic. There were 27 species printed on the chart. Two now prominent species: Common Blackbird and Pied Currawong were not included on the list. This suggests that in 1981 these were not considered among the 27 most widespread species. However, Taylor (1983b) later revealed that “this was done with a view to marketing the charts interstate” (which never happened). The instructions for version one of the chart are:



Enter the maximum number of birds of each species seen at one time within 100m of your house for each 7 day period. The date of the 1st day of each 7 day period is entered at the top of the chart. Only record the numbers of birds dependent on the 100m area e.g. birds on the ground, perched on fences or hawking over trees and shrubs. For birds only seen flying over and not dependent on your area or seen beyond 100 metres, underline the record. Only the maximum number of birds seen needs to be recorded. However, add the following code letters for breeding records: C = RAOU nest record card, N = nest with eggs or young, F = dependent fledglings. Note - in leap years week 9 has 8 days.


These instructions contained several problems and are ambiguous. It instructs to “only record the numbers of birds dependent on the 100m”, yet allows for recording birds “not dependent on your area or seen beyond 100 metres”, with underlining of the record. This requires assessing whether a bird was dependent on the area. It also raises the problem as to how far beyond 100 metres, an observed bird, could still be included. My pilot study questionnaire of 1988 (pages 16 & 17) asked how people interpreted the distance instruction. The results suggest that observers mostly kept to the intent of the 100 metre radius. As the instructions allowed that underlining could indicate various possibilities, this ambiguity confuses interpretation of the underlining of observations. Fortunately few observers used the underline option. Those that did, often had two numbers in one cell. Dual data can not be used. If the two counts were simultaneous, such as ten Galahs perched when 25 flew over, then the maximum is 35. If those two events happened at different times, then the maximum is 25. When doing computer data entry, the original intent of any double notations or underlining is unknown. It is clear in looking at the data compiled for the ABR in the early years, that the underlining of an observation was ignored. The higher number in a cell was the one used, in this Galah example 25, unless there was some clear indication that the counts should be added. This method was retained in inputting old data into the new system. With these problems it is unfortunate that version 2 of the chart repeated this instruction. There is a possibility that recorded abundance of some species could show an artificial drop from higher levels in Years 1 to 12 than for later years. Recording of breeding was simple. Observers recorded breeding by N and F and a variety of individual styles that progressively evolved. Breeding observations noted as N on the charts are described as “activities at nest” in the species accounts. There was no C type breeding records noticed during this analysis.

Version two of the chart was designed by McComas Taylor and improved on the appearance and clarity from version one. It was issued about June 1985 and was used for Years 5 to 12. This chart continued the problems of underlined observations, determining dependence and out of area records. There were 41 species printed on the chart. The instructions for version two of the chart are:



·       Enter the day of the week of 3 July at the top of the chart. Each seven day observation period will begin on this day of the week, except in leap years when Week 9 has eight days.

·       Enter the maximum number of birds of each species seen at one time within 100 meters of your house for each seven day period.

·       If birds are not dependent on your area (i.e. are not feeding, perching or hawking), or if they are seen flying over or are outside your area, then underline the record.

·       Add the following code letters for breeding records: C = RAOU nest record card, N = nest with eggs or young, F = dependent fledglings.

·       Record the exact dates of arrival of migrant species and any unusual records.

·       COG will supply a free replacement for each Garden Bird Survey Chart received at the end of the year.


Stocks of version two ran low in early 1993. There were discussions on whether to issue new charts improved only in appearance and maintaining continuity with the same flawed instructions or to change the instructions to match the changes already being promoted informally. The latter course was chosen.


Version three of the chart (and later versions) were designed using a computer design package, so improved substantially on appearance and clarity and are much easier to use. It also incorporated many developments to comply with the new COG database, such as new breeding codes. It was designed by Philip Veerman and Kirk Rockett and issued in June 1993. It was used for Years 13 to 17. There were 50 species printed on the chart. The instructions for version three of the chart are:

(as issued previoulsly)
-----Original Message-----
From: Duncan McCaskill [
Sent: Tuesday, 4 June 2013 10:25 PM
To: Paul T.
Cc: canberra birds
Subject: Re: [canberrabirds] Counting C Myna in GBS

You had it straight, but have been confused by this discussion.

There is no requirement that birds recorded in the GBS be "using" your garden (or more correctly, your 3.1 ha site that probably includes your garden) in any way. Apparently, the very first rules in 1981 did include a requirement that birds be "using" the site in some way, but as Philip wrote, that rule was explicitly removed in the 1993 version of the chart. Given the vagueness of what could be considered "using" a site, I doubt if anyone took much notice of the rule. (I don't know for sure. This was a very long time before my involvement with COG and the GBS.) 

Yes, GBS sites can and do include neighbouring bushland and other "non-garden" areas. There is no height limit. You can count birds flying over no matter how high. (A few weeks ago I recorded a Wedge-tailed Eagle flying so high it was invisible to the naked eye. I only saw it because I was watching some much lower Pelicans through binoculars.)

The issues originally raised in this email chain were about trapped and killed mynas. Yes, count mynas in your trap. As  Philip said, keeping the rules simple is important to avoid confusing people.

The only issue is to not count dead birds (like mynas killed in your trap) more than once - dead birds tend to stay dead and don't move on. A recently dead bird is strong evidence that it was recently alive in your site. So, for example, if you find a road kill Barn Owl in your GBS site count it - its very likely the only Barn Owl you'll see in the week. But if, say, you find a Noisy Miner that has killed itself flying into your lounge room window sometime while you were out, then don't add it to the count of other alive Noisy Miners that may be around -  since you don't know when it was alive. The GBS count is a count of the maximum number (alive) of birds seen during the week at the one time

Come to the next COG meeting on Wednesday June 12. You can sign up for the GBS and pick up a chart. I will be giving a short talk on the GBS which hopefully will make things clear.

Duncan McCaskill
Garden Bird Survey Coordinator.

On 4 June 2013 20:14, Paul T. <> wrote:
Howdy Folks,

I don't have a GBS, and by the sound of it I'm probably glad. <grin>  Far less questions this way.  However, I'm sure I've heard people talk about recording something on their GBS that has flown over.  Given Chris (below) says that "the count is about the birds that use your garden".... how is something flying over "using your garden"?  I had thought up until now was that the GBS count related to any bird seen within the boundaries of your GBS, including I think what we ended up terming a vertical cylinder above it of unspecified height.  So what is this about it being birds that use your garden?  Also, don't GBS cover bushland etc as well?  I thought I had it straight, but now I'm confused?


Paul T.
Higgins, ACT.

At 07:29 AM 4/06/2013, you wrote:
What happens if the bird never actually had time to use the garden but only died there ? and then where the gardens only use was to bury it there?. Its a tricky one to answer so over to you Philip.

From: Chris Davey <>
To: 'Sue Lashko' <>; 'Paul Fennell' <m("","ptf");" target=_blank>>; 'canberrabirds chatline' <m("","canberrabirds");" target=_blank>>
Sent: Sunday, 2 June 2013 2:20 AM
Subject: RE: [canberrabirds] Counting C Myna in GBS

The count is about the birds that use your garden.  Birds can use a garden in all sorts of ways. If it happens to use it to die then it still gets counted.
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