On Starlings and Mynas

To: "'Michael and Janette Lenz'" <>, "'chat line'" <>
Subject: On Starlings and Mynas
From: "Philip Veerman" <>
Date: Sun, 12 Aug 2012 15:49:48 +1000
Thanks Michael,
I agree with all those points and you added some bits I did not know from ANU. We are not dealing with a sealed system. Birds are mobile and impacts in one place may be expressed slightly different elsewhere. Mynas were around my place in big numbers in recent years, up till last year. This year there is an occasionally seen usually maximum of two here. I don't know of anyone removing them close to my GBS area, so I assume removals from further away are impacting. 
Next point, Starlings are more adept at feeding on wet pasture than dry, (and more adept at feeding on wet pasture than Mynas). Several years of dry conditions are likely part of the story, as are recent regimes of lesser levels of watering of sports grounds and school grounds. These are all likely factors contributing to the change over. Along with competition between the two. The special thing about these TWO species is that they compete both for nests and for food (not totally but partially). None of the other species mentioned in that paper do both. Thus there is more scope to suggest a causal relationship between these two.
For what it is worth, I don't think I have ever seen a confrontation between Mynas and Starlings. Competition can work without having any direct conflict.
As for which way Mynas could impact non-cavity nesting birds such as Superb Fairy-wren, Grey Fantail and Silvereye. Yes for the last two that is a absurd and lazy comparison. Completely irrelevant. They could have looked at Yellow-rumped Thornbills which at least feed on some of the same things (small ground living insects).
-----Original Message-----
From: Michael and Janette Lenz [
Sent: Sunday, 12 August 2012 12:18 PM
To: chat line;
Subject: [canberrabirds] On Starlings and Mynas

In his recent discussion of the Grarock et al. Myna paper Philip Veerman states “It is abundantly obvious that the Common Starling decreased as the Common Myna increased, that is described in the GBS Report as the most likely relevant interaction to any other species by the Myna.”

I wonder about the closeness of that interaction.

There is no doubt that the Myna would win in any direct confrontation with a Starling, and competition would be strongest during the breeding season for nesting sites. However, the strong decline of Starlings occurred just as much in Myna-free areas as in those with Mynas present. For example, the more than 80 pair breeding population at the ANU (from my earlier surveys) largely vanished without a Myna being seen, nor were the Starling breeding sites (mainly in buildings) occupied by other species. In 2008 I revisited the breeding birds of Ainslie, and found Mynas and Starlings sharing the same building for nesting, albeit using different entry holes to get under the roof space or in the wall cavities, but both species would often sit fairly close to each other on the roofs, and singing.

As Philip also points out in the GBS report, the Starling starts to nest earlier than the Myna (a fact that would give it some advantage). The more slender-built Starling would also be able to use hollows with a smaller entrance, Mynas could not access. Outside the breeding season, one can sometimes see both species in mixed flocks, but overall the Starling tends more frequently to visit pasture, sports fields and the like.

To me, all this points to many factors impacting on the Starling, with the Myna being one, but not necessarily the key factor.

And this brings me back to the Grarock et al. paper.

Factors other than the Myna with a negative impact on populations of other species are not properly explored (see also Geoffrey Dabb’s and Mike Braysher’s earlier comments). And it would have to be explained in which way Mynas could impact non-cavity nesting birds such as Superb Fairy-wren, Grey Fantail and Silvereye. The biology of those 3 species would largely exclude direct interaction with the Myna. Yet predation (e.g. Pied Currawong, cats etc.) may be a far bigger issue with those or the increasing footprints of buildings at the expense of green space, drought etc.

In this context, the House Sparrow is of interest. It has declined worldwide (with some significant exceptions, e.g. the city of Berlin with a stable House Sparrow population). Many factors have been identified that could explain its decline. Grarock et al. add the Myna for Canberra to that list of negative factors. Yet there is agreement in the wide literature on House Sparrow decline (none quoted by Gararock et al.) that no single factor satisfactorily explains the world-wide decline. 

Michael Lenz

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