Re: FW: [canberrabirds] Red-rumped Parrot abundance

[David Rees <>]

Geoffrey

Over this time period Canberra has grown, where I now live was a sheep paddock a bit over 10 years ago.  Red rumps are very common here in Harrison, esp in winter.  Would not be surprised if grassy areas as managed in a suburban setting  - nature strip, roadsides, drainage easements, parks etc. now offer more in the way of winter food opportunities than the former nibbled sheep paddock did. The Governments erratic mowing is probably helping their cause. Red rumps are pretty tough, confiding things, saw a pair going through the fag ends and other impedimenta right outside the Liquorland in Gungahlin town centre a week or two back. 

David

On Wed, Jun 7, 2017 at 6:45 PM, Geoffrey Dabb <> wrote:

Perceptions about this sort of thing are always interesting.  While the accumulated statistics are of great value, I think some caution is needed in interpreting them.  I would not myself regard the RRP as a ‘garden bird’.  However it feeds on seeds (mainly grasses and forbs) in open areas, including nature strips.  The garden bird survey can include parts of nature reserves, playing fields, median strips etc so I would think the GBS over time is likely to reflect the character, over time, of the 3ha ‘garden sites’ included in it.   

 

In the 2016 GBS report the RRP has an ‘abundance’ (numbers related) rank of 34.  A comparison with some other species is below.  As a matter of interest I have added the F% (percentage of GBS sites where recorded in the course of a full year).

 

11.  A King-Parrot (92.2)

17. Eastern Rosella (96.9)

20. Little Corella (75)

26. Gang-gang Cockatoo (60.9)

32. Rainbow Lorikeet (40.6

34. RRP (53.1)

35. YTBC (68.8)

42. Superb Parrot (31.3)

 

The general statistics should be more relevant to this species.  In 2016 the RRP had a rank of 21 in ‘total records’. This is in front of the King-Parrot, for example, possibly due to seasonality factors.

 

While the CBN general table excludes GBS data, it seems that GBS data is included in the BirdInfo PDFs (perhaps contrary to the statement in the heading). This would be significant as the total number of weekly GBS sheets is considerable.  Anyway, two of the graphs are below.  Note that they end in 2013.

 

 

One point about the general statistics is that apart from the GBS data (if included) a large component is collected by a relatively few industrious observers, so certain areas might be  disproportionately represented.

 

Now, turning to general impressions my own is that, yes, there have been noticeably more RRPs about in areas I visit over the last couple of years.  This is especially so in the post-breeding period after families leave the woodlands and sometimes coalesce.  This might be due to the birds having learned to make more use of rough-mown areas around Canberra, which might offer more food because of recent weather patterns.  One way or other, I would think their presence is food-related.

 

Very happy to be corrected if I have anything wrong. .

 

 

 

From: Duncan McCaskill [m("gmail.com","duncan.mccaskill");" target="_blank">mailto:duncan.mccaskill@gmail.com]
Sent: Wednesday, 7 June 2017 10:37 AM
To: Philip Veerman
Cc: Canberra Birds
Subject: Re: [canberrabirds] Red-rumped Parrot abundance

 

For Red-rumped Parrot, the reporting rate and the abundance measure closely track each other. The abundance measure looks noisier - for example in 2004/05 there were a few records of large flocks at one site, giving a large peak in the graph below.  The average group size has hovered around 5 for most of the survey, with lows around 3.5 in the mid 90s, highs around 5.8 in 1984/85 and 30 years later in 2015/16. The peak of 9.4 in 2004/05 is probably an outlier.

 

 

​ Duncan.

 

On 6 June 2017 at 22:34, Philip Veerman <> wrote:

Actually the abundance statistic from the GBS is the “A” value, the one that has traditionally been used for the GBS graphs in the COG ABR and used in The GBS Reports and BOCG. The R value is, as Duncan indicates, merely the Reporting rate, and has rarely been given prominence in COG information. It is the proportion (in this case %) of observer weeks, at which the species was recorded. This is not abundance, it in no way uses the available information as to the numbers of birds observed. Although there is an obscure connection between the two statistics. If group size was always a constant (such as always one, which it clearly isn’t), then there is a direct connection. The GBS Report explores this connection, as a highlight of the GBS.

 

Philip

 

From: Duncan McCaskill [mailto:m("gmail.com","duncan.mccaskill");" target="_blank">duncan.mccaskill@gmail.com]
Sent: Tuesday, 6 June, 2017 7:52 PM
To: calyptorhynchus .
Cc: Canberra Birds
Subject: Re: [canberrabirds] Red-rumped Parrot abundance

 

Summaries of COG's data for each species are available on the COG website under Our Birds / Bird Info. The Red-rumped Parrot summary sheet is here: http://canberrabirds.org.au/wp-content/uploads/2015/02/Red-rumped-Parrot.pdf (PDF download).

 

This graph of the reporting rate from COG's Garden Bird Survey shows a decline to about 2002, followed by an increase back to 1980s levels. 

 

 

 

Duncan McCaskill

Coordinator, Garden Bird Survey.
​

 

On 6 June 2017 at 17:16, calyptorhynchus . <> wrote:

Do the COG databases and other collections support my idea that RRPs have become more common over the past 20 years in Canberra?

--

John Leonard