canberrabirds

On the subject of species records and observers - species covered and th

To: Geoffrey Dabb <>
Subject: On the subject of species records and observers - species covered and thoughts
From: "Steve Read via Canberrabirds " <>
Date: Wed, 1 Oct 2025 05:53:59 +0000
Hi Geoffrey, all

Am in Victoria this week so can only reply briefly and on my phone.

You have done an interesting enumeration of total species records across cities. But that is only the start of any analysis. The main point of difference that I would add is that eBird in fact provides highly structured data - each checklist contains not only the number of individuals of each bird species observed, it also contains data on the duration of observation, number of observers and length of path (a measure of area sampled). Some or all of those metrics can be used to adjust the total number of records by these measures of effort.

The simplest way to improve the analysis is of course to calculate the reporting rate - the proportion of checklists that contain the species of interest. I suggest doing that before any more sophisticated transformations.

Regards

Steve


Steve Read
0408 170915


On Wed, 1 Oct 2025 at 3:04 pm, Geoffrey Dabb via Canberrabirds <> wrote:

Good afternoon.  I began this little project out of curiosity to see whether the huge numbers of species records we have generated recently could be used to make a comparison of the bird life of Australia’s capital cities.  My conclusion is ‘not really’.  This is because the records are gathered in an unstructured way,  with no easy way of allowing for variations in recording intensity.  However the raw numbers might have some interest.  Canberra ranks first or second (rank shown in brackets) for recording 6 of the species chosen for consideration.

1  Lewin’s Rail (4),

2  Superb Lyrebird (2),

3  Australian Painted-snipe (2), 

4  Grey Fantail (1),

5  Red-rumped Parrot  (1),

6  Yellow-tailed Black-Cockatoo (1), 

7 Crested Pigeon 1980s (4), 2020s (2).

 

I might mention something I noticed.  The big cities are flexing their binoculars. There is a great bias towards large population centres in eBird-style record-gathering.  For two species I compared Canberra and Melbourne, each in its way sending many recorders into the field.   I limited the records to those from eBird.  For comparison I was going to use the period from 1 Jan 2010, totalling the records for 2010s and 2020s, but I found an interesting difference.  Melbourne, with a vastly greater pool for recruiting recorders, has doubled its records between the two periods while the increase in Canberra’s recording intensity is much more modest.   The doubling does not apply to Victoria generally for WWC, haven’t checked further.  There is no possibility that the increases are attributable to more birds having appeared in either place.  WWC  2020s map with the square for Melbourne is shown in attachment.

 

 

 

From: Canberrabirds <> On Behalf Of Geoffrey Dabb via Canberrabirds
Sent: Tuesday, 30 September 2025 12:22 PM
To: Canberrabirds <>
Subject: [Canberrabirds] On the subject of species records and observers - seventh and last

 

I must move this along.  Here is 7th and final one.  Getting easier, perhaps?

 

Beginning in the late 1970s, this species has achieved a marked increase in its urban populations.  This seems to have begun in Adelaide, where the influx was attributed to inland drought.  It has adapted to breeding in suburban gardens, quite noticeably in Canberra.   Now, it might be Australia’s most urban native bird species (as measured by numbers in town versus non-town areas).

 

Seventh species (and last)

1980s map

Adelaide 1462

Brisbane  217

Sydney  96

Canberra  80

Melbourne  22

Darwin  5

Hobart, Perth 0

 

2020s so far (29/09/25)

Melbourne  34,350

Canberra  33,172

Brisbane  19,840

Sydney  18,048

Adelaide  6,682

Perth  2,149

Darwin  1

Hobart  0

 

 

 

 

From: Canberrabirds <> On Behalf Of Geoffrey Dabb via Canberrabirds
Sent: Tuesday, 30 September 2025 8:44 AM
To: 'Canberrabirds' <>
Subject: Re: [Canberrabirds] FW: On the subject of species records and observers

 

Here are two more species.  Some would see these as particularly associated with Canberra, where they are able to take advantage of different feeding opportunities. 

 

Fifth species. This is a common one, being noticed recently even by non-bird-people as present in quite large numbers in the suburbs. It is suited also to Melbourne suburbs, less so to those of Sydney except in the west (Penrith, Camden, just in the 50km).

Canberra  50,580

Melbourne  37,314

Sydney  10,128

Adelaide  4,913

Brisbane  220

Hobart 1

Not in Perth or Darwin

 

Sixth species.  A favourite of some people, often heard in transit.  Go to particular places to find it.  Doesn’t breed around Canberra, so far as I know.  Comparable numbers in Canberra and Melbourne, which have similar large numbers of active recorders, I would think, area for area.

Canberra  17,174

Melbourne  14,824

Brisbane  7,189

Sydney  4,986

Adelaide 4,034

Hobart  2,595

Not in Perth or Darwin

 

One more species to come, then answers and conclusions

 

 

From: Canberrabirds <> On Behalf Of Geoffrey Dabb via Canberrabirds
Sent: Sunday, 28 September 2025 12:46 PM
To: Canberrabirds <>
Subject: [Canberrabirds] FW: On the subject of species records and observers

 

And now a common widespread species.  A comparison of records for different areas indicates, in my view, where you will find the most active recorders as well as giving some information about distribution, and of course where records can be best captured by a square.  A variable polygon of fixed area would be better, but too much work.  I believe ALA maps exclude records where there is poor information about location.  As Canberra is emerging as the recording capital of Australia, an attached image shows the process used here.

 

Fourth species

Canberra  73,886

Melbourne  55,340

Brisbane  49,799

Sydney  28,702

Perth  16,967

Hobart  16,049

Adelaide  10,166

Darwin  56

 

From: Canberrabirds <> On Behalf Of Geoffrey Dabb via Canberrabirds
Sent: Saturday, 27 September 2025 11:53 AM
To: 'Canberrabirds' <>
Subject: Re: [Canberrabirds] On the subject of species records and observers

 

As some of you might have feared, I have a couple more Canberra bird species.  Same procedure as before.  I should mention that Atlas of Living Australia brings together eBird and BirdLife Australia records and those in first RAOU Atlas and in many older sources.  As a guide to distribution, the earlier records are now tending to be overwhelmed by the huge numbers of eBird records, although you can select sources as well as particular decades.  I’ve used all sources, all years.

 

Second species

Not an urban species. The 50x50km square had to be placed carefully to capture enough records to put Melbourne at top of list.  (Compensation for the D’s poor AFL season)

Melbourne  5236

Canberra 4876

Sydney 3698

Hobart 157

Adelaide, Brisbane, Perth, Darwin all zero.

 

Third species

Brisbane 407

Canberra 332

Sydney 249

Adelaide 118

Melbourne 79

Perth 16

Darwin 4

Hobart 3

 

 

From: Canberrabirds <> On Behalf Of Geoffrey Dabb via Canberrabirds
Sent: Friday, 26 September 2025 5:20 PM
To: Canberrabirds <>
Subject: [Canberrabirds] On the subject of species records and observers

 

Using the Atlas of Living Australia, I made a 50km square for each of the eight State/Territory capitals. Each was positioned to catch most of the available records of this native bird species, while also taking in the relevant CBD.  This was the result  –

 

Brisbane 2203

Melbourne 1226

Sydney 966

Canberra 430

Hobart 154

Adelaide 49

Darwin 4

Perth 1 (museum specimen only)

 

Hints - As ALA records go, these are low numbers for a species, White-faced Heron for example having over 700,000 records. Most records of this species are near the capitals, presumably indicating acceptable habitat and following the rule that records generally come from the most convenient places for observers.  However, South Australia is an exception because most records (253 in one 50km square) were more than 50 km from Adelaide.

Which species?  Please don’t reply to list in case people want to think about it.

 

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