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Atlas methodology, Little Button-quail

To: "Birding-aus" <>
Subject: Atlas methodology, Little Button-quail
From: "Robert Read" <>
Date: Sat, 24 Mar 2001 12:01:59 +0930
Recently there has been some discussion about lower reporting rates of some species in the present Atlas than in the first Atlas.  Tabulated below are reporting rates for Little Button-quail for the 9 one degree squares centred on Alice Springs.  This is a parochial approach because I prefer to talk about areas that I know a little about. 
 
Data for Atlas1 are taken from the published book, hence they are classes bassed  on the size of the dot on the map.  Data for Atlas2 are taken from the NT Atlas website  http://birds.rhyme.com.au/virtmap/oz/71/400_300/133_51_19/23_40_49/birds.html
 
It can be seen that in Atlas 1 LBQ were reported in only 3 of the squares, while in Atlas 2 they have been reported in all 9.
 
The most likely explanation for this is that the probability of seeing LBQ is directly proportional to the distance walked across grassland.  Beating around 2 ha search areas is a good way to find them.  They are generally not seen while travelling on roads, but may been seen on little-used and overgrown bush tracks.  The high reporting rate in 22/133 is probably a reflection of a high proportion of 2 ha searches in this square.  The low reporting rates for 23/132 and 23/134 are a reflection of the fact that most surveys for these have come from a few popular tourist spots that are not good LBQ habitat.
 
A second possible factor is that most observers for Atlas1 would have been using the Slater 1st edition field guide.  This does not show how to distinguish LBQ and Stubble Quail as they fly away from the observer when flushed.  Many Atlassers may not have been able to distinguish them with confidence. 
 
The final conclusion is that comparisons between Atlas1 and Atlas2 range from difficult to impossible.
 
Robert Read
Alice Springs
 

Atlas 1

Atlas 2

Lat

Long

No surveys   

Surveys with   LBQ

No surveys

Surveys with LBQ

      %

22

132

26-50

0

71

6

8%

22

133

26-50

0

170

38

22%

22

134

6-25

<10%

45

5

11%

23

132

>50

0

118

2

2%

23

133

>50

>10%

1364

132

10%

23

134

>50

0

113

3

3%

24

132

>50

0

27

1

4%

24

133

>50

>10%

157

17

11%

24

134

26-50

0

94

6

6%

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