"Do Common Mynas significantly compete with native birds in urban environments?" new paper

[Denis Wilson <>]

My Two Bob's worth.

Having only read the precis, my comment is that I thought the main impact of Common Mynas was likely to be on breeding hollow competition, rather than on feeding competition.

The fact is, they are introduced species and any breeding hollow they occupy is one less available to native birds.

Merely planting more native plants in proximity to houses is not going to solve anything.
Perhaps if people were educated to seal their roof spaces properly that might be MORE productive, but what's wrong with both active (trapping) and indirect control (education) programs?

In my village (outside the ACT) there is a single old building (an old Cheese Factory) which supports breeding populations of Starlings and Common Mynas, and as long as that is allowed to continue, there will be an on-going source of these pest species. Simple precautions on modern houses, and observation by residents, can greatly help reduce the breeding population of both species. 

Denis Wilson

On Sun, Sep 18, 2011 at 8:22 PM, Philip Veerman <> wrote:

I can't guess at the relevance of Euro34.95. I would assume they are serious. It should be credible research but is it broad enough to be relevant in a wider area. Kim Lowe was for a long time in charge of the Aust Bird Banding Scheme. Richard Major has researched urban birds for a long time. He won the best presentation by a student when COG hosted the RAOU congress in 1989, when I won the other best presentation award for my talk on the GBS and told of my intention to do a book on the GBS. I don't know of C. E. Taylor.

 

I suggest though that comparing the feeding behaviour of the Common Mynas with just two other species (if that is what it was) has limited relevance. These things always need to be taken in context. It talks about in this study area, which very likely is true within also the things they tested. If as Damien pointed out lots of bar graphs that show that common mynas essentially do things in the same proportions as other species relative to their abundance then that in no way shows a low impact. The critters aren't doing anything evil, disproportionate to their abundance but if they are at high abundance, surely that may still mean that they can be having a high impact.

 

I still think trends of abundance from the GBS are reasonably strongly suggestive of them having an impact, on starlings and quite possibly parrots.

 

Philip

 

 -----Original Message-----
From: martin butterfield [
Sent: Sunday, 18 September 2011 1:19 PM
To: Robin Hide
Cc: Canberra Birds
Subject: Re: [canberrabirds] “Do Common Mynas significantly compete with native birds in urban environments?” new paper

Alas.  If we only had a spare Euro34.95 we might know whether these folk are serious or not.

Martin
A bit more info:

Most of these findings were done using surveys, i.e. point counts.  The species they tested for interspecific aggression were Willie Wagtail and Magpie Lark.  Hollows were detected from occupancy, that is they surveyed an area and followed all hole-nesting species (from Lorikeets to Cockatoos they say) to ascertain the number of hollows used (as a proxy for the number present).  They then have lots of bar graphs that show that common mynahs essentially do things in the same proportions as other species relative to their abundance.  Most of this work in the October-February period.

I suspect that a longitudinal study of shifting behaviour within a site over time during which a change in abundance of Common Mynahs will yield different outcomes (which is what I assume Kate's work is doing).

Damien

On Sun, Sep 18, 2011 at 1:06 PM, Robin Hide <> wrote:

A controversial new paper?
Robin Hide

Lowe, K. A., C. E. Taylor and R. E. Major (2011). “Do Common Mynas significantly compete with native birds in urban environments?” Journal of Ornithology 152(4): 909-921.

Keywords: Common Myna -  Acridotheres tristis  - Competition - Aggression - Urban.
Abstract: In Australia, the introduced Common Myna (Acridotheres tristis) is commonly believed to aggressively displace native birds and outcompete them for food and nest resources. However, the current paucity of scientific evidence makes it difficult to devise appropriate management strategies for protection of urban bird populations. This study investigates the way in which the Common Myna uses the urban environment and interacts with other species while foraging and nesting in Sydney, Australia. The bird community varied between habitat types along an urbanisation gradient, and the abundance of the Common Myna increased significantly with the degree of habitat modification. Surveys of the frequency of interspecific interactions revealed that the Common Myna did not initiate a significantly greater number of aggressive encounters than did other species. Focal observations of two potential native competitors showed that despite foraging in close proximity, the Common Myna rarely interfered with feeding activity. Assessment of natural tree hollow occupancy found that Common Mynas used significantly fewer tree hollows than did native species. Analysis of nest site selection indicated that Common Mynas chose to nest in more highly modified habitats, and in artificial structures rather than in vegetation. These findings suggest that, in this study area, Common Mynas have little competitive impact on resource use by native bird species in the urban matrix. The logical conclusion of these results is that the substantial efforts currently directed towards culling of Common Mynas in heavily urbanised environments is misdirected, and resources would be better directed to improvement of natural habitat quality in these areas if the purpose of control is to enhance urban bird diversity.

-- 
Denis Wilson
"The Nature of Robertson"
www.peonyden.blogspot.com