Myna traps and numbers

To: "'Michael & Janette Lenz'" <>, "'chat line'" <>
Subject: Myna traps and numbers
From: "Philip Veerman" <>
Date: Thu, 18 Jun 2009 22:22:12 +1000
Oh yes, clearly there are several factors applying to population changes of all species, these two no less than others. One of the other things is soil moisture. Starlings like feeding in damp substrate more than dry and the dry conditions impact on them but it probably makes no difference on Mynas. Clearly Michael or anyone else may choose to be surprised or see a connection as we see fit. We can only consider if data supports or disproves things. I say Starling and Myna have very similar dynamics. Their annual abundance pattern is very similar, their timing of breeding is very similar (see the graphs in the GBS Report). Given a choice they will eat the same things in the same places and nest in similar places. So I reckon of all the species we have in Canberra for which we have a lot of data from the GBS, I find it hard to come up with any other two species that are so similar in so many ways, that do compete for both food and nesting sites (and nesting in hollows creates much more competition than building a nest in a tree) for which an increase in one matches so closely a decrease in the other, as we have in this example. If anyone else can nominate another situation with anything like as close a match, then I'd like to see it. There is certainly little if any evidence from GBS trends that changes in either species have affected any other species where we can suggest a credible link, where the evidence is so supportive as it is with these two.  Sure the Red-rumped Parrot and the Kookaburra declined with the increase in the Myna and the Pied Currawong. Is there a link? Well maybe but hard to be sure as there are so many other factors operating and in each case any causation is based on just one aspect.
Philip Veerman
24 Castley Circuit
Kambah  ACT  2902
02 - 62314041
-----Original Message-----
From: Michael & Janette Lenz [
Sent: Thursday, 18 June 2009 6:32 AM
To: Philip Veerman; chat line
Subject: Re: [canberrabirds] Myna traps and numbers

While there may certainly be possible interactions between Mynas and Starlings (espec. regarding competition for nest sites), I would still be surprised if there is overall a direct link in the rise or fall of one of the species due to the fall or rise of the other species.
Starling and Myna have very different dynamics. The Starling decline was Canberra-wide and occurred in too many places without that Mynas were present. And now Starlings are coming back in areas with still good Myna numbers as I could also see last year during my Ainslie survey. Some buildings had both species present as breeders.
Anyhow, perhaps Martin could do again his good work and prepare, his time permitting, a graph on the A values for the Starling we then could compare with the one for the Myna.
Michael Lenz
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