A quartet of Casps

Since the glut of juveniles at the beginning of August, finding a Caspian Gull in London hasn't been an easy task. Repeated visits to Erith Pier drew a blank into mid-September and the bird I had on Thursday was the first showy individual I've seen for a number of weeks. As it happened, that was a precursor to a productive Saturday afternoon at the pier, which produced no fewer than four first-winters.

The first of these was probably the least impressive. I picked it up at around 500 m range as it came to scraps being thrown out by an old lady some way upriver of the pier. In flight it looked a great Caspian Gull, with noticeable pale underwing and crisp tail band. However, by the time I'd walked round to the bird and managed closer views, I was significantly less impressed. The boldly marked greater coverts aren't typical of Caspian and my guess was that it perhaps has a bit of Herring in it somewhere. That said, everything else looks good for Caspian and the bird has even moulted a few lesser coverts already, with these apparent in the deck shot below.

1cy Caspian Gull, Erith Pier, 28 September – such boldly marked greater coverts aren't great for cachinnans, but otherwise it looks good

Really nice in flight, with a classic cachinnans tail

I headed off to get some food for 20 minutes. In the meantime Jamie had arrived and located a first-winter Casp straight away. It transpired to be X09J, a bird that has been regular around the Thames over the past 10 days or so and had previously spent some time at Cromer, Norfolk. It's a bird from the notorious Laussig hybrid colony and isn't the best-looking Casp but, having actually seen it in the flesh for the first time, it's better than I'd been giving it credit for.

Caspian Gull 'X09J', Erith Pier, 28 September 2019

The third bird was the best of the bunch. It was absolutely stunning on the deck: beautiful white head, distinctive face, textbook plumage with diffuse pale fringing to the greater coverts and and classic tertial patterning. The retained juvenile scapulars had that uniform mouse-brown look to them, too. In flight it was quite mucky, with the underwing fairly dark and the uppertail with plenty of barring.

1cy Caspian Gull, Erith Pier, 28 September – a particularly beautiful bird at rest

The fourth and final bird was an absolute unit. Jamie picked it up on the water at distance and, because of its bulk, was initially unsure on whether it was a cach or mich. Scapular and covert patterns, plus the facial expression, certainly favoured the former and that was confirmed when it did a brief fly-past at the pier.

1cy Caspian Gull, Erith Pier, 28 September – a particularly big and bulky bird, the size of some Great Black-backed Gulls

Other bits of note during the Saturday included a Norwegian-ringed juvenile Great Black-backed Gull. Black 'JJ285' was ringed at a nest approximately 10km west of Bergen on 23 June 2019 and was still in that area on 21 July. My sighting was the first away from here.

Great Black-backed Gull 'JJ285', Erith Pier, 28 September 2019

Small numbers of Yellow-legged Gulls remain around the Thames, most of which are first- or second-winters, albeit with the occasional older bird around.

1cy Yellow-legged Gull, Erith Pier, 28 September

2cy Yellow-legged Gull, Erith Pier, 28 September