Friday, October 16, 2009

Juvenile Slaty-backed Gulls & Friends

I have no classes on Wednesday so I decided to take a walk along the beach in front of my dorm and what I found there was quite unexpected, 3 juvenile large gulls! It's been 2 years now living in Beppu and I've never seen anything else except the same old Vegas, Taimyrs, Black-headeds and Black-taileds. Guess it has something to do with the typhoon last week. I took so many photos and found that they're mostly blurred or shaking, which I've just realized that it is because the image stabilizer was not being turned on. I felt stupid for that. Here are some of the photos that are acceptable of the special species I've found that day.

Delicate different angle of head can result in different shades of color

Same here for the color of the primaries

I tried identify all these juvenile birds but one of them was quite problematic. I concluded that all of them are Slaty-backed Gull(Larus schistisagus) due to their dark appearance(though differs in amount of brown and white feathers) and brown(not black) primaries. 1cy Vega Gull has blackish primaries, while Glaucous or Glaucous-winged has the same shade of brown as their body. The only problematic one was the darkest individual among the 3 and also the smallest one too. It even has a metal ring on its right leg. Today I emailed the pictures to Mr.Ujihara of the Japanese Gull Site for his opinion. Let's wait and see what this guy will turn out to be.

Here it is, the problematic guy. Note the ring on its right leg.

The primaries are also darkish brown, not blackish.

But what makes me happy the most is not those dark first-year gulls, but this snowy 1cy Mongolian Gull(Larus mongolicus) indeed. This is the first time for me to see a very typical first-year Mongolian Gull. It stood out among all other gulls with its snowy-white appearance. It seemed to be a little bit smaller and weaker-billed than Vegas too. First-year bird of this species is ironically the easiest stage for identification.

1cy Mongolian Gull with Vega, Black-tailed and Taimyr Gull

It seems to have some of the second-year's wing pattern too.

Another bird which looks like a Mongolian Gull to me. It has 7 black-tipped primaries and rather long-winged impression. Black markings on primary coverts are also unsual for most Vegas. However, the bird was relatively small when compared to other Vega Gulls, which reminds me of a Taimyr Gull. The bird also has yellowish-pink legs that sort of got me confusing too.

Why not all the gulls be so typical like this Vega?

This one is strange because of its left strange white p9

Well, sometimes cormorants also wanted to be a star.

This is the same bird as in the first picture. Late evening light makes it looks much browner.

And this is the problematic dark one; totally different bird in different lighting condition.

The last bird that came in the evening, the 2cy Slaty-backed Gull with the dark individual.

Another bird that I find quite interesting is a probably third-winter Taimyr Gull(Larus heuglini taimyrensis). I find it interesting because this is the first time for me to see this form in Japan. The bird reminded me of what I usually see in Thailand. I always thought that the 'taimyrensis' population in Japan and in Thailand should migrate from totally different territories(which doesn't make sense with the term 'Taimyr'), since they look so different. But now it's the first time for me to see what I used to see when I go birding in Thailand. The shade of grey on its back is cleary darker than Vegas and it's also distinctly smaller and slimmer-built too.

Its p9&10 are still the old ones while most of other primary feathers are growing new.

Okay, I'll end this entry up with a series of the common Black-tailed Gulls. They actually have lots of interesting variations, but their abundance just sadly wipes away all my keenness in identifying. Lots of strange gulls are already here, hope more and more will continue to come this winter.

The amount of brown pigments on the head is actually very interesting.

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