Thursday 13 October 2016

Eastern Marsh Harrier

I was in Mie on Saturday (Oct 8) and one of the highlights was a fly-by Eastern Marsh Harrier. My personal experience suggests Eastern Marsh, or any harrier for that matter, is surprisingly unusual in the Tsu / Matsusaka area. In fact I don't recall ever having seen one there off the top of my head. Perhaps it's a absence of suitable roost sites within easy flying rather than a shortage of habitat to hunt across.

Aging and sexing immature Eastern Marsh is a total mystery to me. Primarily because I don't see them often enough or well enough and no two birds seem to look the same to my unattuned eye. All a bit off-putting. Thank goodness the only Pied I've seen in Japan was an adult male! However these few images of yesterday's bird, flying below the seawall, allow a better appreciation of the markings and structure than my usual blurred, against the light attempts.

There really isn't much help in the literature that I have access to but I'll put my head on the block and say this is a 2CY male.

A wonderful surprise to have a bird come by just below eye level. By the time I jumped out of the car it was already slightly behind me but fortunately it swerved and dropped towards the field before resuming its course.

That the flight feathers have been replaced is one obvious reason here why it isn't a juvenile and the very extensive brown on the underparts leads me to doubt it could be as old as third calendar year; hence the 2CY theory. Of course I could be wrong and even if I'm right it's probably just a lucky guess. Why male? On this view the almost plain bases to the outer primaries suggest male to me, I suspect that a female would have fairly prominent barring across the bases of the outer primaries much as on the secondaries and inner primaries. I'm even more likely to be wrong on this point.  

Luckily for me something caught its eye at this point, it twisted sharply and swooped towards the field providing an excellent opportunity to see more features.

It's easy to read too much into a single image but this shot captures the slight build indicative of male. The thin tarsai and bill also suggest male.


  1. Seen this species many times now but a good photo totally eludes me.

    Surprised it is so rare down there.

  2. It's not rare in Kansai Stuart, I just don't see them in Mie. I see tons in winter near Lake Biwa but they are mostly distant birds coming in to roost.