Tuesday, November 13, 2007

Tasmanian Thornbill.

There are two very similar 'brown' thornbills in Tasmania, the Brown and the Tasmanian. I should confess here, that in my early days of birding in Tasmania, without the aid of illustrated bird guides, I rather 'fudged' my sightings of Tasmanian Thornbills. If it was in a wet forest, it must be a "Tasmanian", and vice versa for the "Brown" in drier areas. I must say that in the main, that was probably correct, but these days I'm a little more thorough!
I've had a bit of an issue with some of the field guides, largely when the description includes statements like, "bill larger in Brown". This may be true, but unless you have the other to compare it with, or very familiar with both species, it's not the most useful piece of information. I should say here that I'm not setting myself up as an expert on the issue of 'brown' v 'tasmanian'. In fact, while looking through the many images of the 2 species that I've taken, I sometimes got it wrong. The reality in the field is that you're often looking at birds in deep shade or high in the canopy and that's when it gets interesting.
I have published the accompanying images to hopefully aid observers, as there doesn't seem to be many images on the internet of the Tasmanian Thornbill. Many have their own method of differentiating the two, but the rufous colouring on the primaries and pure white undertail feathers (lack of buff), stand out. I hope the images prove useful!

9 comments:

Graeme said...

This is a wonderful site. You have motivated me to visit Tasmania!! I'll probably be there over Xmas period whcih I hear is a good (albeit busy!) time of year. Thanks for the inspiration.

Murray Lord said...

Hi Alan,

I mentioned to you ages ago that I had seen a trip report by a bird tour company claiming Tasmanian Thornbill at Peter Murrell. Recently I read another trip report - by a very experienced birder, but on their first visit to Tas - claiming the same thing. I would wager that they are all Browns there, what do you think?

With practice it's possible to tell them apart by call, but the poor descriptions in the field guides are no help on that front. I think the Tasmanian's call is less harsh than the Brown's; it lacks the hard grinding notes that Browns make.

BirdingTas said...

Hi Graeme,
Thanks for the great rap! I do feel rather a weight on my shoulders, I only hope that Tassie lives up to your expectations. There are, as you rightly commented, a lot of things happening over the Christmas/New Year in Tas.. Something for just about every taste.

BirdingTas said...

Hi Murray,
I was going to mention those trip reports. I've been in the Peter Murrell Reserve many times and haven't yet seen a single Tasmanian Thornbill, but many Browns. It's not as if the 'Tasmanian' is difficult to find elsewhere, so there's no pressure to look for them there or "fudge" them!
As far as calls go, I didn't feel I could adequately differentiate them in writing! But, I think the 'Tasmanian' is far more melodic and 'liquid'. Habitat has always been a good starting point and I'm not aware that either species wanders far.

John & Shirley Tongue said...

we have always found the Tasmanian more in denser, wetter habitats - except on King Island, where the Tasmanian is virtually the only Thornbill, and they venture "out" into a much wider range of habitats.

BirdingTas said...

Hi John,
As I mentioned, in my early days I "fudged" my Tasmanian Thornbill sightings on the basis of wet forest area, but that can be misleading. Where the Tasmanian is the 'dominant' species, they're found in a wide variety of habitats, often well away from forested areas, for example, the West Coast and, as you mentioned, King Island. This leads to the point of the article, more care needs to be taken in identifying these two similar species.

Mona Loofs-Samorzewski said...

I spent ages last year quizzing people on how to tell the Brown and the Tasmanian apart and the white 'fluffy' undertail coverts seemed to be the one most people referred to. I had never knowingly seen a Tasmanian so I was most excited to finally confidently ID one right below our house (dense wet gully).

What would be really useful Alan, would be to have some pictures of both together on this blog, if that's possible? They're all Tasmanians on this page aren't they?

BirdingTas said...

Hi Mona,
I did originally intend to post both together. However, the Brown Thornbills shots were taken in bright conditions, and the Tas Thornbills in deep shade. I felt that they therefore would be misleading when comparing. I have used the white 'fluffy' undertail coverts, to diagnose Tasmanian, it's a good indication, but not infallible. The rufous colouring on the primaries is better, as is the greyer appearance and less streaked appearence on the breast.(All needing knowledge of both Thornbills). It is often difficult when viewing conditions are poor, and as I said, more care needs to be exercised when differentiating. It's been interesting looking at many images of both species, but I repeat, I'm not setting myself up as an expert!!

Mike Tarburton said...

G'day Alan
Thank you very much for the notes and photos on the Tassie Thornbill. I also found the field guide comments about bill size pedantic and useless. Wish I had seen your blog before spending the last two weeks in Tassie for some of the thornbills I saw I had trouble classifying.