White's Thrushes in Taiwan (1 Viewer)

I'm hoping someone on this list might be able to cast some light on the status of these birds in Taiwan, because I'm hopelessly confused!!!

Firstly, there seems to be some uncertainty as to whether White’s Thrush (Zoothera aurea) is a species distinct from Scaly Thrush (Zoothera dauma).

* Clements (5th edition - 2004) lumps them

* Howard & Moore 3rd edition splits them

* Sibley & Monroe (1996) lumps them

* Clement & Hathway (Helm Thrushes guide – 2000) lumps them.

Any views on this?


Even if the split is accepted, there seems even more uncertainty as to which birds occur in Taiwan.

* MacKinnon & Phillipps (A field guide to the birds of China - 2000) and de Schauensee (The birds of China - 1984) both state that race horsfieldi is resident, with races aurea and toratugumi wintering.

* Clements 5th edition (2000) split horsfieldi as a separate species, Horsfield's Thrush, occurring in Japan

* A check-list of the birds of Okinawa prefecture with notes on recent status including hypothetical records - Bulletin of Okinawa Prefectural Museum, Volume 22, pages 33-152, 1996 also show horsfieldi occurring in Okinawa, but as a race of dauma

* Howard & Moore 3rd edition show horsfieldi as a race of dauma, but state that it is endemic to Indonesia.

* Clement & Hathway also show horsfieldi as endemic to Indonesia, but split it as a separate species, Horsfield’s Thrush. They go on to state that they believe that the classification of Taiwanese birds as horsfieldi is "mistaken". They make no mention of this species / race occurring in Japan.

Clement & Hathway go on to state that aurea occurs in Taiwan in winter, and believe that race toratugumi is synonymous with aurea. Things then get even more confusing!!!

On one hand they state that “Breeding birds in … Taiwan … have previously been separated into the race affinis, but whilst it is recognized that birds in this area require further investigation they are here considered inseparable from nominate (dauma) birds.”

Further on, they state “… birds taken in Taiwan and previously separated as hancii and affinis are here considered synonymous with aurea …”. I am therefore totally confused as to whether these affinis birds are now considered to be aurea or dauma!

Finally, under the section on Horsfield’s Thrush, they state “There are no recent breeding records of any White’s Thrushes (Z. dauma group) on Taiwan, where the race aurea is known to be an uncommon or rare winter visitor”, which appears to contradict their earlier statement about affinis “breeding birds in Taiwan”. Taiwanese birder Wayne Hsu, however, assures me that there are recent breeding records, and has even sent me photos of this species taken in Taiwan in August 2002.

:h?:

Does anyone know what is going on here, where is horsfieldi found, and which races / species are found in Taiwan? Any help very gratefully received!!

Thanks.

Gruff,
I think I saw a posting of yours through the OB list-server. You are looking squarely at one of the major conundrums of avian taxonomy. You pretty much have to pick your poison on this. At least for the birds of the Oriental region I have come to rely increasingly on the taxonomic treatments of E.C. Dickinson, et al, with the superiorly documented HM 3° Ed. The split of aurea from dauma seems to be well founded on voice and size differences (Martens & Eck, 1995), with the split White's Thrush (Zoothera aurea) being bitypic, and with both races, aurea, and toratugumi wintering but not breeding on Taiwan. The cited taxon hancii, sometimes associated with the nominate race Zoothera dauma dauma, should be more properly associated (according to HM) with the nominate Zoothera aurea aurea and has been subsumed by the HM within this taxon. The Taiwanese breeding birds (their types have been examined) are considered by the HM to be Scaly Thrush (Zoothera dauma dauma). The taxon affinis coined to describe Malaysian wintering birds are also considered to be nominate dauma and have again been subsumed by the HM in Z. d. dauma. Recent treatment of race horsfieldi of Zoothera dauma as a full species in it's own right may be unfounded (see Schodde & Mason, 1999). The HM maintains this as a race of Z. dauma. The only range that I know for race horsfieldi is in the Greater Sundas (Sumatra, Java, Lombok).

Gruff, I know that this is not what you want, and is in large part a reiteration of what you have just explicated, but in many cases one has to just decide to follow one taxonomic treatment and be aware that others may see it differently. For the Oriental Zoothera my money is on Ed Dickinson's treatments.

A Question:
Are you sure that the Clement's 5° Ed. (2000) has Zoothera horsfieldi as ranging in Japan? I do have the text version of this volume and it states: Mountains of Sumatra, Java, Bali, Lombok and Sumbawa. I would suggest that there might have been a previous edition (perhaps followed also by the cited record from Okinawa prefecture) that so stated, erroneously.

Thanks Steve, that's very helpful. It sounds like I need to get hold of a copy of Dickinson et al - do you have the full reference, please?

cuckooroller said:

A Question:
Are you sure that the Clement's 5° Ed. (2000) has Zoothera horsfieldi as ranging in Japan? I do have the text version of this volume and it states: Mountains of Sumatra, Java, Bali, Lombok and Sumbawa. I would suggest that there might have been a previous edition (perhaps followed also by the cited record from Okinawa prefecture) that so stated, erroneously.

Click to expand...

I don't actually have a copy of Clements - I was going on the Avibase on-line checklist, in Clements order, for Japan - http://www.bsc-eoc.org/avibase/avibase.jsp?region=jp&pg=checklist&list=clements which show it as a separate species occurring in Japan. This, of course, may be an error on Avibase!!

Thanks again for your help with this.

Gruff Dodd said:

Thanks Steve, that's very helpful. It sounds like I need to get hold of a copy of Dickinson et al - do you have the full reference, please?

Click to expand...

Gruff,
Which reference do you need? Yes, Avibase is quite a valuable resource for a number of people lacking the inclination or the money to buy text versions of various books, however, and I can't really fault Denis Lepage considering the tremendous amount of time that he has invested in preparing and managing the site, it does have mistakes. The citation for the occurance of race horsfieldi in Japan is apparently due to the fact that someone at some time considered it as being the race of Z. dauma occuring in Japan. Many times mistakes in the so-called "grey literature" of birding hearsay become esconsced and handed down through the years. I think that everyone now agrees that race horsfieldi, or Z. horsfieldi if one wants to consider it a species, ranges only in Indonesia.

Thanks Steve - very useful indeed. Thanks also for the reference, received via e-mail.

Totally agree about Avibase, and indeed the whole Denis Lepage site - absolutely outstanding resource. Makes you wonder how we managed before the internet!

Cheers.

Does anybody know what the current thinking is on the racial identity of the resident Taiwanese Scaly Thrushes. I recently photographed a resident (breeding) bird and the local birder I spoke to stated the the resident birds are racially / visually distinct from the wintering birds, but he was unsure what subspecies were involved. Happy to forward on images if interested

I found a2005 paper by Hsu and Collar that do not give ita name:
http://orientalbirdclub.org/wp-content/uploads/2012/09/Hsu-Taiwan.pdf .
I suggest Z. dauma klimi.

Thanks for the link to the paper. I wonder if any work has been done on these breeding birds since 2005? The bird I saw was nesting / carrying food, so was certainly breeding.

Cheers
Mark

I have not found any more recent work on these birds. I jumped the gun on Z. dauma klimi. Swinhoe named this population in 1863. Oreocincla hancii. The male specimen was from the mountain forests of the interior of Taiwan. Named for Dr. Hance.
http://www.biodiversitylibrary.org/item/35130#page/307/mode/1up .

mb1848 said:

Named for Dr. Hance.

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Actually (as stated in the paper) named after Dr. Hance (i.e., in his honour), not for him (at his request)