Is it possible that the CP are following a normal trend? The numbers appear to follow the rainfall pattern as the graph dips back towards the norm in 2012. We had a great deal of rain in 2010 which might have led to stronger breeding, then the rain has gradually become much less to this year, so less breeding. From my charts:
2010 rainfall 47.5mls
2011 rainfall 27.00 mls
2012 rainfall 32.00 mls
That said there were 19 CP’s on the line at the back of my house last week – the biggest group I have seen – usually there are 6 or so living here. The weather was bad and they probably thought they would get a feed over the back fence. On that day there were 61 SC Cockatoos and 49 Galahs.
Cheers
Jean
From: martin butterfield [
Sent: Tuesday, 28 May 2013 8:34 AM
To: Duncan McCaskill
Cc: canberra birds
Subject: Re: [canberrabirds] Paucity of Crested Pigeons? - GBS Data from continuous sites
Duncan
I agree that it looks like a genuine drop, and from your graph yesterday, a widespread one.
Hopefully some of the biologists in this group will be able to suggest reasons for this. The kite I would fly is to note that one of the problems with Spotted Doves invading Alice Springs was their competition with the native pigeon species.
On 27 May 2013 22:42, Duncan McCaskill <> wrote:
Here is another chart showing the Crested Pigeon "A" value from 2003 to 2012.
The red line for the whole GBS. The blue line is restricted to sites that were operating all 5 years before 2012 (from 2008). That is 49 sites from 2008 onwards, but dropping down to only 25 sites for 2003. It looks to me a lot like a real decline.
On 27 May 2013 17:25, John Layton <m("bigpond.com","johnlayton2");" target="_blank">> wrote:
As I watched a group of Eastern Rosellas feeding among oak mast not far from home during the weekend, they were joined by a lone Crested Pigeon. It struck me that I’ve seen very few Crested Pigeons in the vicinity for several months. Certainly none of the large 30 to 40-bird flocks that were prevalent round here previously, and very few smaller groups/flocks. Perhaps this may be because they’ve spread further afield due to greener pickings since the drought. Has anyone noticed a similar reduction in their numbers?
John K. Layton
Holt.
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Martin Butterfield
