I sent a private email about this to Paul, but agree with JJ about the
unlikelyness of Tas Thornbill at PM. I too have been there countless times
and never seen one. I've also heard a number of other local birders express
doubt in those records. But I think passing through or otherwise vagrant
can't be ruled out.
White "underpants" is the best ID feature in my opinion. Also if you get a
photo, the difference in breast striations is definitely noticeable. I've
found the colour of the wing panels difficult due to light. Calls are
different but I find field guide descriptions poor, and have relied more
obviously learning from listening after visual IDs.
Tas Thorns usually only in genuine rainforest or very wet mixed forest, and
on islands without Browns. I was told in a zoology subject at uni that the
distribution of Tas Thorns is based on being excluded by Browns, which out
compete Tas, so they should only very very rarely be found together (and
never in mixed flocks, as has been reported at PM). I don't know the
reference for this claim though.
Regards, Jeremy
On Sep 18, 2012 4:34 PM, "Murray Lord" <> wrote:
>
> Dave
>
> I reckon these things become self fulfilling prophesies - a few people
> claim Tasmanian Thornbills at Peter Murrell in trip reports, then other
> people go there expecting to see them and don't look as closely as they
> need to. Understandable, particularly if you have already ticked Tasmanians
> at another site.
>
> The two species are just very difficult to tell apart. Personally I find
> the rufous primary panel on Tasmanians to be the most useful character;
> certainly more reliable than the alleged white underpants. I looked into
> their calls a while ago (but haven't ever got around to writing anything
> up). With practice you can distinguish them on calls but it is hard to
> describe the difference. Tasmanians don't make the harsh grinding notes
> that Browns often do.
>
> The confusion in several field guides doesn't help. The description of the
> Tasmanian call in Pizzey duplicates another author's misquote of a
> nineteenth century description of the call by Legge; Legge actually used
> those words to describe the call of Brown Thornbills. And a photographic
> guide has gone through several editions with what in my view are two photos
> of Tasmanian Thornbills to illustrate the Tasmanian and Brown Thornbill
> species accounts. It's no wonder people struggle! And yes I have pointed
> those mistakes out to the relevant authors.
>
> Murray
>
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