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17 November 2010

Thrush headache

Hi all,

I always thought that the Japanese Thrush male adult was ONLY like this (and therefore always thought that its illustration in the Robson had been a little bit botched !) :

with a strong contrast head - mantle/wings

… until I saw this stunning bird 2 days ago in the Botanical Garden :

I told myself : woaah, so nice bird ! An adult male, exactly like the illustration of the Robson ! Ok, but all my contrasted head - mantle males of before, how should I call them now ?

- In the Robson (edition 2006), there's absolutely nothing about this pattern (both plates and texts). Very strange.

- In the Brazil (thanks Florian !), there’s an illustration of this kind of plumage with the legend: 1st winter male.

Not convinced at all, I search on Internet and found something very interesting on OrientalBirdImages, especially the pics of Jonathan Martinez, a French birder who’s living in China, in the Hunan province. He took pics at mid-June 2010 of juveniles, females and males (http://orientalbirdimages.org/search.php?Bird_ID=2464&Bird_Image_ID=44540&Bird_Family_ID=&p=6), in a Japanese Thrushes breeding population. Today, I send him an email to have confirmation that those males were adults and even breeding ones.

He answered this (sorry, in french, please use Google traduction) :
« Pour tout t'avouer, ces thrushes m'ont également laissé perplexe. J'ai une bonne population nicheuse dans le Hunan en Chine et je n'ai pas encore vu un seul mâle nicheur qui ait un pattern classique comme décrit dans de nombreux guides, sans fort contraste manteau-tête, tout les mâles que j'ai pu observer sont identiques à ceux de mes photos. J'en viens à me demander si les oiseaux qui nichent en Chine ne serait pas différents de ceux qui nichent au Japon, j'ai trouvé très peu de choses dans la littérature mais n'ai pas eu encore trop le temps d'approfondir, dans tout les cas il y a quelque chose d'étrange, et je n'ai rien trouvé qui mentionne que la population qui niche dans le centre de la Chine soit une sous-espèce différente. A mon avis il y a matière à creuser».

He wrote, I resume, that among the 10 pairs he have observed over there, he have never seen males without strong contrast head-mantle like described in the majority of the identification guides. All its pics definitely show adults breeding males !

So, different races of Japanese Thrush ? In my humble opinion, the very black males could come from North-Est Asia (Japan, Korea...). Have a look at the blogs of the Land of the Rising Sun birders.

Now, I want to show you a mysterious bird that I have observed last Tuesday in the Botanical Garden. That's a tricky one isn't it ? Look this grey-blue mantle/wings, the contrast head-mantle, the black breast, the bluish spots on the flanks... Why not a 1st winter male Japanese Thrush ?
Thoughts/suggestions/confirmation welcome !


  1. Hi Sebastien,

    yes, definitely a headache those thrushes... And interesting idea, with the 2 different populations.

    First a small correction: your first type of male is called "1st summer male" in Brazil, the "1st winter male" in Brazil looks like the bird in your last pictures (so confirms your ID).

    Still I also don't really understand why we would get so many 1st summer plumaged birds here now, I would assume that they have moulded to adult plumage by now...

    Ok, but I wait of the comments of those who know a bit more about birds than me :)

    Ah Sebastien, one suggestion: maybe you could put all your photos of all the different plumages of JT (and also GBT) you photographed on a flickr (or similar) album, that would be great for discussing...

  2. Hi Florian

    I think no doubt any more

    All those three-coloured black/grey/white Japanese Thrushes with yellow eyering are male adults, not 1st winter (1st summer?!, how it could be ?) coming from.... This is the question !


  3. Hi all,

    I've never seen such a black-backed individual before. I always assumed the black-headed birds with the grey backs were adult males, too. Interesting to hear about other morphs/subspecies.
    Regarding the 1st winter/immature/first summer issue - I just think that there's a bit of variation/overlapping of plumages and moulting stages which are not covered in the guide books.
    Given the fact that sometimes not even species can be told apart I wouldn't be too devastated to not being able to tell the ages apart.

  4. Ok, one more try to understand:

    Bird 1 above fits the plate in Brazil labelled "first summer male"
    Bird 2 fits the plate labelled "adult male"

    "first summer" means the plumage acquired after the first winter, correct?
    So these birds are breading in this plumage in their first summer, before moulting into adult plumage before the following winter.
    And what we get here now are just both plumages, first summer birds that not yet have acquired their adult plumage and full adults.
    What you think?

  5. The Thrush get its definitive adult plumage after 1 year, that`s all.
    The bird 1 is a full adult already, it will never become the bird 2
    There are 2 adults males of 2 different areas.
    Jonathan Martinez, who’s living in the Hunan province, has never seen the `type bird 2` in summer, during the breeding season. All the breeding males he observed are `type bird 1`.