Possible Tasmanian Morepork in Victoria

To: Jeff Davies <>, 'Steve' <>, 'Birding Aus' <>
Subject: Possible Tasmanian Morepork in Victoria
From: Chris Corben <>
Date: Tue, 11 Jun 2013 12:57:03 -0500
Hi all

Interesting subject!

So how convincing is the evidence that Tasmanian Boobook is only a winter visitor to the mainland? Or could it be like Pink Robin, with migration to the mainland in winter but also breeding in the wetter forests of Victoria and southern NSW?

I'm particularly interested in this, because the Gould's Wattled Bats of Tasmania seem to me to be a different species from the widespread form on the mainland. Migration is unknown, and the Tasmanian form is found in summer in the cool, wet forests of Victoria and southern NSW, including the Otways. I don't think anyone agrees with me on this, by the way! But an interesting side of it is that it seems the habitat of the Tasmanian form on the mainland is seriously undersampled acoustically, which is by far the best means for seeing the difference. Otherwise people would have noticed the difference long ago. The point being that people who work with bats are vastly more likely to be exposed to the much more widespread form than the more restricted Tasmanian form.

It might seem this would be less the case with Boobook Owls, but maybe not if our samples are highly biased. For example, what if a high proportion of the specimens available are from road kills, then this sample is likely to be very biased against birds breeding in the wet forests, but less biased against Tasmanian migrants in winter. It could also have consequences for our understanding of identification criteria, since if you operate from the assumption that the Tasmanian birds are winter visitors, then the apparent distinctness of the form could be diluted by occasional specimens from the wet forests in summer, seeming to contradict the general view of how the forms differ. It often turns out that a better understanding of the temporal and spatial distributions of similar taxa can lead to a clarification of identification criteria, just as understanding their ID can lead to a better understanding of distribution.

Cheers, Chris.

On 06/10/2013 10:19 PM, Jeff Davies wrote:
G'day Peter,

It's the combination of three or four features all in the one bird that
suggest Tasmanian Boobook, yellow eyes, small white spotting surrounding the
face and elsewhere if you could see it eg hindneck, and as John has said
white markings in the belly presenting more as overlaid white circles with
less of a tendency towards longitudinal shapes. Steve Clarke also felt that
the bird looked particularly small, ssp leucopsis is over 10% smaller than
ssp boobook.

Cheers Jeff.


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