Thursday 28 September 2017

Those alba Great White Egrets again!

I feel I keep banging on about how the status of Great White Egrets seems to have changed in Japan. I'm suddenly seeing so many alba, where are they coming from and why? If this increase is real rather than just being my impression then presumably something at their continental point of origin is driving the dramatic uptick in numbers I'm getting.

It wasn't until early 2012 I saw an alba in Kansai, an alba and modesta side by side; they looked so different! I'd had an eye out for them for years and thought I was probably overlooking very similar taxa but after that I was sure I couldn't have been overlooking them, at least not totally. I didn't see any the following winter then found three in the 2013-14 winter, one of these was in Shikoku where a local birder told me it had been a good winter for them there. There were no more blank winters but numbers remained low. I saw my first summer bird in June of last year then in the winter 2016-17 they seemed to be popping up all over the place. Nevertheless a flock of about 40 in Mie came as a shock. It probably came as a shock to the lone modesta on the lagoon to find so many 'monsters' that were oblivious to its best efforts to drive them off.

Last week I saw my first here since spring, again in Mie, and it stood out like a sore thumb as they always do. As there were four modesta on the same tidal inlet and I was able to get a few good comparative shots.

A sore-thumb alba, it isn't necessary to have direct comparison to see how much more massive they are.

One of  the four modesta sharing the tidal inlet.

These three images give a good indication of just how much bigger and bulkier alba is.

When it comes to seeing who's boss there's just no contest...

Check out the thickness of the tarsus and tibia, the size of the feet, the thickness of the toes... these birds are chalk and cheese.

A couple of old images showing the respective appearance in (presumed) breeding condition.

May 5th modesta with rosy-pink tibia and (mainly) black tarsus, green lores and black bill. This looks the deepest bareparts flush of the courtship period.

May 26 alba with legs fully flushed pink, tibia and tarsus, pale green lores and yellow bill. The intensely pink legs suggest this bird is in breeding condition yet that the bill hasn't begun to turn seems very odd unless this population doesn't become black in breeding condition. Perhaps this is an exceptional individual and perhaps age could play a part. The several early May birds I've seen on Mishima have a very dull (not blackish) tarsus and the bill varies from bright yellow with just a darker tip to the upper mandible (not unlike modesta later in summer as the black of breeding condition disappears) to what I'd describe as a golden-brown at any distance, as if a first coat of dark paint was failing to mask the yellow beneath. 

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