Brown Treecreeper reporting rate and the overloaded map

To: "'Michael and Janette Lenz'" <>, "'wallaces'" <>, "'chat line'" <>
Subject: Brown Treecreeper reporting rate and the overloaded map
From: "Philip Veerman" <>
Date: Sun, 16 Sep 2012 13:44:06 +1000
Good points from both of you. I suggest the usual system (when such things are published) is to provide one map that gives the number of surveys done for all sites, which is a constant for all species and other maps separately for each species. The existence of incidental records obscures any such analysis but really there is no way around this. On face value, I agree that the colours and sizes of the 'dots' should surely be reversed - the larger and more colourful, the better the sighting/reporting, and the fainter and paler, the least. Although maybe it requires being seen in practice to assess if that looks good. But I also think that Steve's map was not addressing the issue of the reliability of the reporter or accuracy of the identification (these are separate issues and better approached in other ways - as in whether the record is on the system at all). I expect his use of reliability is just about the usefulness of the sample size (based on a start point that all records are accurate identifications). I think that on a quick look whilst the map is worth having, it is visually confusing, noting that it is full of symbols but only The cells with the squares are ones where Brown Treecreeper has been reported, so that the ones without squares are not, and so are minimally relevant to the species. I suspect that the idea that Steve has put forward with his map would be much easier to assess for usefulness by picking a far more common and widespread species than a Brown Treecreeper. That way I am guessing the information would be easier to see, by virtue of fewer gaps.
-----Original Message-----From: Michael and Janette Lenz [ Sent: Sunday, 16 September 2012 9:34 AM
To: wallaces; chat line      Subject: Re: [canberrabirds] Brown Treecreeper reporting rate and the overloaded map

Steve - I am only Michael Lenz' wife and not a 'bird-watcher' though also trained in scientific disciplines and have been 'around' bird-watching for most of my life, so please accept comments in the light of this.
I really like you analyses of the various species which you have been putting on the chat line - thank you.
Certainly seeking to overcome problems of reporting rates is a good aim - however, I think the complex map is not very helpful. 
On a minor point, the colours and sizes of the 'dots' should surely be reversed - the larger and more colourful, the better the sighting/reporting, and the fainter and paler, the least ?  But more importantly, the spread indicates the ease and prevalence of reporters, rather than the reporting itself.  Quite obviously, there will be more reporting at the easily accessible areas.  Next, and much harder to quantify, is the reliability of the reporter. For example, if Michael is the only person to record the sighting (eg. north eastern tip of Lake George which is very inaccessible, but which he visits) then that could be taken as a 'sure' record, given his life-time experience and dedication, however, if I went to the lower slopes of Mt Ainslie on a stroll, I could 'record' but might be mistaken.  Unfortunately, this is an awful minefield to get into, for while I readily admit my lack of knowledge, many others do not - nor should they, perhaps, as it sets up a hierarchy which we would not want in COG and people would become discouraged.
For these, as well as the reasons you set out (nil reporting etc. does not mean that there were no birds there) I would think that it is not particularly useful to follow up with 'reliability indicators'.  Most people will 'know' that a reporting rate map has its flaws, but that these are perhaps insurmountable in terms of absolute 'scientific' proof.
Hopefully this input will increase discussion.
Subject: [canberrabirds] Brown Treecreeper reporting rate and the overloaded map

Attached is a map showing the reporting rate for Brown Treecreeper from 1981 to 2011.
It illustrates one way to overcome one of the fundamental problems with reporting rate maps: they do not show how many sheets contributed to the reporting rate. The basic problem is that the number of sheets submitted for a gridcell is an important factor in determining the reliability of the reporting rate.  Any species reported on the only sheet submitted for a gridcell gets a 100% reporting rate for that gridcell. A gridcell with a reporting rate of zero means little if only one sheet has been submitted and means nothing if no sheets have been submitted for the gridcell.
The map indicates the quality of the reporting rate by the circles in the gridcells.  The smaller the circle and the less obvious the colour, the better the reliability of the reporting rate. Cells with red circles indicate a very low reliability, yellow is better but the data should still be used with caution and very small green or clear circles indicate the best data reliability. The cells with the squares are ones where Brown Treecreeper has been reported. For instance, the map indicates that around Gunning is a good place to see Brown Treecreeper (high reporting rate with a good number of sheets submitted) but B08 may not be as good (it has a high reporting rate but only one sheet has been submitted).
Gridcells without any sheets have nothing in them on this map but this needs to be improved to distinguish them more easily from the 50+ sheets cells. Also the number of categories for the number of sheets could be changed (eg 0,1-2, 3-10, 10-50, 50+) or reduced.
While I recognise that map is currently overloaded and the graphic design could be greatly improved, does including a reliability indicator improve the ability to get useful information off the reporting rate map?
<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