Unidentified Gulls

Always learning. And I never seem to have enough knowledge to identify all the birds I see…! Here are a few images of ‘unidentified gulls’ seen at Choshi. I have a good idea on some of them but there remain niggling doubts. On others, I am less sure. Have a look and let me know if you can help..!

Bird 1: Unfortunately only this one image. I am thinking it must be a Vega Gull but that underwing looks incredibly pale and the black on the wing-tip suggests thayeri?

Bird 2: this bird has a primary pattern that fits thayeri and the mantle is paler than the nearby Vega Gulls. But that head looks too 'fierce'.

Bird 2: The same bird. Note dark eye and pale mantle. Hmm...

Bird 3: Clearly a 1st winter (2nd calendar year) Common Gull-type but is it henei, kamtschatschensis or even a Mew Gull?

Bird 3: Same bird. Note short bi-coloured bill.

Bird 4: A 1st winter (2nd calendar year) bird. Note smallish, rounded head and generally pale plumage.

Vega Gulls

Vega Gull (Larus vegae) is the most common large white-headed gull at Choshi in winter. I saw several hundred and below are some images in various plumages with some personal comments. Although Vega Gull is considered a separate species by some, others consider it a subspecies of American Herring Gull or Herring Gull. I can see why.

Adult winter in alert posture. This individual has relatively light head-streaking. Orange/red orbital ring.


Near-adult (note black markings on bill). Note dark eye (quite common in Vega) and relatively pale legs (a good proportion of Vega have more 'raspberry pink' legs but certainly not all).


A very 'clean' headed bird, recalling


A more typical winter head pattern with thin streaking on the head and thicker, more blotchy streaking on the neck.


Black on wing-tip varies but most have black on p10-p5 with some including black markings on p4.


Another typical bird with black p10-p5


Black reaches p4 on this bird. Darkish eye.


2 cal yr bird showing dark secondary bar. Pale panel on inner primaries reaching outer secondaries.


2 cal yr. Beginning to gain some grey scapulars. Tail pattern typical.


A very striking and exceptionally 'hooded' bird. Note the fleshy pink legs.


Feeding Vega Gulls (with Black-tailed Gull bottom left). Note variation in wing-tip pattern. The flying bird has typically 'raspberry-pink' legs.

Slaty-backed Gulls

Given the recent putative Slaty-backed Gull in London, I paid close attention to the Slaty-backed Gulls in Choshi. I saw around 45 examples of what I identified as Slaty-backed and photographed several. As with most gulls, this species is variable and, although there are a suite of features (eg pale eye, dark ‘intermedius LBBG-coloured’ mantle, shortish raspberry pink legs, pale yellow bill etc) that distinguish a typical Slaty-backed, there appear to be many examples with one or more of these features lacking. Below is a selection of my images of Slaty-backed Gulls with some associated personal comments. I am in no way qualified to comment on the London bird, except to say that if I saw it at Choshi I wouldn’t have hesitated to identify it as a Slaty-backed.

Please contact me if you spot any inaccuracies in my commentary or have any additional comments.

The first Slaty-backed Gull I saw. This individual has a relatively bright bill
No2: looks dark-eyed but in the field the iris was pale-ish, albeit heavily speckled
No3: a typical individual with a pale eye, dark (Lesser Black-backed-coloured) mantle and strong bright pink legs
No3 in flight: same bird as above. Mantle appears lighter at the different angle.
No4: from below
No5: from above. The mantles of some birds look relatively pale in strong light. Note no mirror on p9.
No5: Same bird.
No5: close up of head and underwing pattern. Eye is speckled and could appear dark at distance.
No6: a dark bird with heavy head streaking. 'String of pearls' obvious.
No7: an immature bird but note very pale underwing in strong light.
No7: Same as above. Note how the underwing looks darker in different light.
No8: the legs appear relatively pale and thin (taken in strong light)
No9: eye appears dark. mirrors on p10 and p9.
No9: Same individual as above. Eye looks paler in strong light.
No10: Eye looks dark on this individual. Bill pale yellow with slightly brighter tip.
No11: 'String of pearls' clear on this bird. Heavy streaking on the head.
No12: A typical individual in terms of mantle colour, pale eye, primary pattern and leg colour.
No12: same individual as above next to a Vega Gull (with Black-tailed Gull behind) for comparison.
No13: Pale eye, dark mantle and relatively heavy head streaking.
No13: Same bird as above. Note no mirror on p9.
No14: Typical. Pale yellow bill, sturdy bright pink legs.
No14: same bird as above in flight. 'String of pearls evident, large mirror on p10 with smaller mirror on p9.
No15: Note no mirror on p9.


Gulls… They say that, as a birder, you either love them or hate them. Well, I am definitely in the ‘love’ category, even though I find the large white-headed gull complex an identification challenge.

Living in Beijing, a very dry and land-locked metropolis, sightings of any gulls near to home are few and far between. So the opportunity to visit Choshi, just east of Tokyo, was too good to miss.

This port, situated on the edge of the vast Pacific Ocean, is home to hundreds of fishing boats and I saw huge catches of yellow-fin tuna, mackerel, sardines and some larger species, including what looked like swordfish. The sheer quantity of fish, and its associated waste and by-catch, means that there is plenty of food for gulls and, during winter, they are attracted here in their thousands. The most common gull by far is the Black-tailed Gull, an east Asian endemic, closely followed by Vega (a Herring Gull lookalike) and Black-headed Gulls (ssp sibiricus). Among these are reasonable numbers of Slaty-backed Gulls with a few Glaucous-winged, Glaucous, Common (ssp kamtschatschensis) and the odd Mongolian Gull (Larus cachinnans mongolicus) mixed in. During my visit I also saw a Ring-billed Gull (the first Japanese record of this American species was as recent as 2002).

Access is easy and free – I had no problem at all walking around with binoculars and a camera and the great thing for photography is that you are generally looking north from the harbour towards the water, meaning that the winter sun is mostly with you.

If you are interested in gulls, this is as close to heaven as it gets. However, Choshi is not just about gulls – many more sought after species can be seen well here. The local Black Kites (ssp lineatus or ‘Black-eared Kite’) also enjoy the bounty provided by the fishing boats and there are good numbers of Temminck’s and Pelagic Cormorants plus Black-necked and Slavonian Grebes just offshore. A single Harlequin Duck near the lighthouse at Cape Inubo was a nice addition to my visit and Dusky Thrushes were common in suitable habitat. Around Cape Inubo there were also Blue Rock Thrushes, Japanese White-eyes, Bull-headed Shrikes and a single Brown Thrush.

I will follow this general post with some detailed posts about specific species but, in the meantime, I am posting a selection of images to give you a feel for the place.

Getting there: Choshi is within easy reach from Tokyo and Narita airport and a day-trip from either is very doable. Catch any train from Narita Airport to Narita and change for the hourly local service to Choshi, which takes around 90 minutes (cost cGBP10). The staff at the airport are incredibly helpful and will point you in the right direction and give you advice on purchasing a ticket. Once at Choshi, it is a 5-10 mins walk to the north to reach the river Tome, from where you can walk east along the whole length of the harbour for 3-4 km (the whole stretch is good for gulls). Further along the coast to the south-east lies a famous lighthouse at Cap Inubo. It would probably take 2-3 hours to walk to this point from the station, so a taxi is a good option if you want to explore this area (but beware, taxis in Japan are expensive – it cost me almost GBP 20 pounds for the 10-minute journey from Choshi town centre to the lighthouse). I found only one hotel in Choshi where the staff spoke any english – the Choshi Plaza (half way from the station to the river on the right hand side) – which, at GBP50 per night, is reasonable value in Japan.

Best areas: there are boats all along the harbour wall running from just east of the Tome bridge to the sea, with three fish markets interspersed. The best area for viewing gulls depends on the activity in the harbour and which boats are offloading their catch but, about half-way along, there are a couple of good areas of sea wall parallel to the road which are good places to scan – hundreds of gulls rest here and there are good numbers all day.

A sardine boat returning to Choshi port after a night on the seas

Fishermen warming themselves around a fire at Choshi port

Yellow-fin Tuna on sale, most of which will be destined for Tokyo sushi

A fresh catch of sardines, Choshi

Adult Black-tailed Gull, Choshi, Japan

Adult Vega Gull, Choshi, Japan

Slaty-backed Gull, Choshi, Japan.

Adult Glaucous-winged Gull

First winter Glaucous Gull, Choshi, Japan. Note the dark-tipped pale bill

Black-headed Gull ssp sibiricus

Common Gull ssp kamtschatschensis

Black-eared Kites are common scavengers around the port

Dusky Thrushes are common at Choshi in suitable habitat

Pelagic Cormorants are fairly common at Choshi

Hundreds of Temminck's and Great Cormorants can be seen along the sea wall at Choshi. This one is a Great.

Black-necked Grebes are common winter visitors to Choshi