Sunday, 11 February 2018

Choshi (1): Thayer's Gulls

Next stop on my trip to Tokyo was Choshi Harbour, for gulls and nothing else but gulls! After having spent two whole days either on board ship or in the ferry terminal, I was exhausted when the ferry finally pulled in to Tokyo Harbour Monday night. Fortunately, the logistics for the transfer to Choshi couldn't have worked out better as there was, first of all, a hotel located conveniently just 200 metres from the terminal building (Hotel Azur Takeshiba; a bit pricey if all you want is a shower and a bed, but not beyond budget (and I wasn't in a fit state to travel anywhere, completely drained of energy and swaying around wildly with motion sickness)) and, secondly and even more conveniently, a direct bus to Choshi Train Station leaving from Hamamatsucho Bus Station at a sensible hour the following morning (operated by Kesei Bus and leaving from Gate 1). At about two and a half hours' travelling time, the bus was almost as fast as the train, without the need for multiple confusing line changes that could have thrown a spanner in the works at any given moment! The bus pulled in at Choshi late morning leaving me with a short walk to my hotel ('Kamome' Hotel, which I am told means 'seagull', so top marks for appropriateness), where I quickly dumped a bag and began the short march out to the harbour. Coming from Taiwan (where max. fifteen gulls at any one time in the gull 'hot spot' of Dung Shr Harbour), Choshi is about as different as you can get. It is probably therefore best described as being 'not for the faint-hearted'!


Thayer's Gull Larus thayeri both was and wasn't a target whilst at Choshi. In my mind, it was most certainly the best thing I was likely to come across, but I also knew that it was technically a vagrant and that my chances of actually finding one there might be slim (though I had done my best to hedge my bets with a three-night stay). So, you can imagine my surprise when I picked out a first-winter sitting amongst the gulls on the very first stretch of harbour wall I happened to look at! This bird was about as 'Thayer's Gull' as one could get, with its small size, 'pot belly', weak bill, short legs, and longish primary projection (with 'frosted' look). In flight, it got better, with entirely white underside to all flight (and tail) feathers and 'Venetian blind' effect through the outer primaries.


Having found one with ease on my very first afternoon out in Choshi, I was then expecting to come across more similarly straightforward Thayer's Gulls, but in fact I saw none until my very last day. On my penultimate day, I ran into a local birder who informed me of an area where he had seen two adults that very afternoon. This spot got penned in as the one to hang around in for my final morning in Choshi and it duly produced a cracking adult after not too much waiting around. The trick with this bird (as it seems to be with all birds) is to go for breakfast or 'take a leak' or something, as that's precisely when it will choose to appear. I was half way through my breakfast sandwich when this striking individual flew into the harbour in front of me, meaning the sandwich had to get part wolfed/part wanged as I had to immediately start running after it!


In the end, this bird performed so well that I got a very nice series of shots of it on the ground eating a fish (in much the same manner as I had eaten breakfast). In fact, it was so confiding that I also managed a sound recording: the high-pitched piping 'keuw' you can hear above the various harbour noises here is the adult Thayer's Gull. I found this call to be so distinctive that it proved to be a useful indicator that the bird was present in amongst the melee of other gulls.


Once the bird had left the area, I did so myself, only to return a short while later after a brief walk to the harbour mouth. Remarkably, once back at the Thayer's Gull 'spot', I immediately ran into the first-winter of my first afternoon in Choshi standing conveniently out on low overhead wires. It was nice to get closer and sharper shots of this individual, though sadly it chose to fly off almost immediately as I tried to walk around to the other side of it to get better front end shots.


Neither the adult nor the fist-winter returned in what remained of the morning, and I threw in the towel at about 11:00 to head back to my hotel and depart for the airport. The only other bird worth posting here is probably a single adult Vega Gull Larus vegae with a 'Thayer's-like' wing pattern that had been hanging around the same area as the actual Thayer's Gull a couple of days before. At least now after having seen a genuine Thayer's Gull, precisely how this individual differed from the 'real deal' was much clearer (and such birds have caused problems for me before in Taiwan, e.g. here). In addition to being larger and bulkier, the 'fake Thayer's Gull' showed dark grey on the underside of the flight feathers (as opposed to pure white) and black on the under primaries (as opposed to grey). Furthermore, this individual had white (of the mirror) extending onto the outer web of P9, oft-cited in the literature and being 'out' for a 'pure' Thayer's Gull. Interestingly, though, the real Thayer's had a much paler eye than the 'fake' one, suggesting that eye colour is not especially important in separating Thayer's from potential 'lookalikes'.


I guess I really couldn't have asked for more in respect of Thayer's Gulls from Choshi, what with seeing two age classes, a 'lookalike' individual, and obtaining a sound recording. So much to play with with just these three individuals, and these were far from being the only interesting birds on offer there! Above photos taken at Choshi Harbour, Chiba Prefecture 6-9/2/18.

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