subspecies Blue Rockthrush | Wajima jp (1 Viewer)

HouseCrow · Jun 25, 2019

subspecies Blue Rockthrush | may 2018 | Wajima, Japan > ssp philippensis

After plenty of red-bellied/red-breasted philippensis Blue Rockthrush in Japan, on 25 may last year I came across this male Blue Rockthrush that appeared all blue. It was foraging on the Wajima seaboard in Western Japan.
According to Brazil pandoo is rare in Japan (https://books.google.nl/books?id=HkpyDwAAQBAJ&pg=PA348&lpg=PA348&dq=monticola+saxicola+pandoo+japan&source=bl&ots=FKX19hSQhL&sig=ACfU3U2bwd4PQdzIzaD3dCJpkMwFdKkj-w&hl=nl&sa=X&ved=2ahUKEwiduMKMmITjAhVOPFAKHXyDBuoQ6AEwC3oECAkQAQ#v=onepage&q=monticola%20saxicola%20pandoo%20japan&f=false)

What would you say this is. Is pandoo an option or are there philippensis with less red on their breast.

full record with more photos in that series here: https://www.inaturalist.org/observations/27617463

hope to hear from you

cheers,
Gerben

Otarujef · Jun 25, 2019

ssp. pandoo

Hi Gerben!,

from the Mark Brazil Book:
"M.c.pandoo from Central and Eastern China is accidental to offshore
Korea, Japan, and Taiwan".
The all blue seems restricted to ssp. pandoo.

the thrush where you are in Wajima appears to be in parallel proximity to China, and the map in Mark's book as well shows both areas in the "summer" range.

My humble opinion would be it is a ssp. pandoo.
Chestnut and blue have been reported in some cases on the ssp. philippensis,
but NOT on ssp. pandoo (so far of course).

I came across this on a US state bird checklist for definitions:
Casual - seen many years but not all, at least 3 and less than 9 of last 10 years.
Accidental - seen once to several times, but less than 4 of last 10 years.
(Rare would be hundreds of miles or full continents off course)
Hope this helps.

Jeff

HouseCrow · Jun 25, 2019

In town the 'normal' philippensis was rather conspicuous, singing from rooftops in the evening like Blackbirds in Western Europe.
I must admit that I only realized it might be a different bird, yesterday when I added the photo to the record on my main japan recorder (https://japan.observation.org/waarneming/view/175117309)
Had i known that it might be something different, I would have made a bit of effort to make better record shots.

It's difficult to find records-listings such as waarneming.nl, they're not there for Japan, I guess. So it's difficult to know how often the species has been seen.
I may have to ask my Japanese contact, but I wanted to have more certainty about this bird's ID first.

So that's 1 vote for pandoo....thanks. Hopefully some others will give it a look.

cheers
Gerben

johnallcock · Jun 26, 2019

It does look promising for pandoo, but I think it's hard to be absolutely sure from this angle. Some birds can have very restricted red on the belly, only seen behind the legs. I'm not sure if these are variant philippensis or intergrades between philippensis and pandoo.

HouseCrow · Jun 26, 2019

True John, it's hard, or impossible maybe to determine its identity.
Are you saying philippensis can have that little amount of red? That would make an ID impossible with the few photos I have.

edit: when I tweak the levels in photoshop, the normal pattern for ssp philippensis appears to be there.
so a probable philippensis.

thanks,

Gerben

johnallcock · Jun 26, 2019

HouseCrow said:
True John, it's hard, or impossible maybe to determine its identity.
Are you saying philippensis can have that little amount of red? That would make an ID impossible with the few photos I have.

edit: when I tweak the levels in photoshop, the normal pattern for ssp philippensis appears to be there.
so a probable philippensis.

thanks,

Gerben

Yes, the extent of red is variable below, and in some birds can essentially be restricted to the undertail coverts. I'm not sure whether these birds are true philippensis or if they are the result of interbreeding between philippensis and pandoo. They are fairly rare but probably worth considering before claiming a pandoo outside the normal range.
Compare these photos from Hong Kong (where most birds are philippensis but pandoo also occurs in small numbers):
http://www.hkbws.org.hk/BBS/viewthread.php?tid=6690&highlight=blue+rock+thrush
http://www.hkbws.org.hk/BBS/viewthread.php?tid=1804&highlight=blue+rock+thrush
http://www.hkbws.org.hk/BBS/viewthread.php?tid=25424&highlight=blue+rock+thrush

Grahame Walbridge · Jun 26, 2019

johnallcock said:
Yes, the extent of red is variable below, and in some birds can essentially be restricted to the undertail coverts. I'm not sure whether these birds are true philippensis or if they are the result of interbreeding between philippensis and pandoo. They are fairly rare but probably worth considering before claiming a pandoo outside the normal range.
Compare these photos from Hong Kong (where most birds are philippensis but pandoo also occurs in small numbers):
http://www.hkbws.org.hk/BBS/viewthread.php?tid=6690&highlight=blue+rock+thrush
http://www.hkbws.org.hk/BBS/viewthread.php?tid=1804&highlight=blue+rock+thrush
http://www.hkbws.org.hk/BBS/viewthread.php?tid=25424&highlight=blue+rock+thrush

Similar intermediates, often referred to as 'affinis' occur occasionally in NE India, from Sikkim to Assam and in S. Bangladesh.http://orientalbirdimages.org/search.php?Bird_Image_ID=110618&Bird_ID=2481&Bird_Family_ID=&Location=

Grahame

HouseCrow · Jun 26, 2019

Interesting stuff John/Graham.
I have been looking around for slightly off standard Blue Rockthrush online or in Japan itself. Not intentionally at the time but still.
It would suggest that in areas where pandoo may turn up, some mixing might occur. Western Japan would be a nice area to find them, but they may actually be rare: first record 1988 according to this article (https://www.researchgate.net/publication/269821519_A_new_subspecies_of_Rock_Thrush_Monticola_solitarius_pandoo_recorded_in_Kagoshima_Prefecture_Japan) No doubt birdwatching intensity has increased since, and so too the likelihood of it turning up somewhere.

I still think that my bird was 'just' a philippensis, but it's interesting to look for blue Blue Rocks in the area.

thanks again all,
cheers,
Gerben

subspecies Blue Rockthrush | Wajima jp (1 Viewer)

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