It's been another pitiful winter for white-winged gulls across Britain, with disappointingly low numbers nationwide and particularly so in the south-east, where they're always thinnest on the ground.

So, it was a bit of a surprise when Dante found this bird with George Gay at Erith Pier just after Christmas. Since then it's become strangely loyal to Beckton sewage works and the adjacent creek at Creekmouth. Sometimes it is one of the only large gulls present!

When I saw it on 28th, the bird was loitering on the sewage tanks and only viewable through the fence. Fortunately I'd come prepared with several loaves, so started lobbing them into the creek. The bird couldn't resist the sound of the squabbling Black-headed Gulls and came in pretty quickly, giving fairly good photo opportunities.

It's only the second Iceland Gull I've seen in London, following the bird I found in Hammersmith back in December 2016 (which, incidentally, has recently returned for its fourth winter running and is now in pristine adult plumage).

In terms of birding, 2020 has picked up where the past couple of years left off – my first full day out in London on Saturday naturally focused around gulls and little else.

It seems we've had a bit of an influx, perhaps caused by the recent winds. Overall numbers were higher – Saturday morning's congregation on the landfill site at Rainham was easily the biggest I've seen all winter. We always speculate as to what cause these influxes – cold weather is usually the answer, but in this mildest of winters it does seem something else is at play. Perhaps when it gets a bit windy offshore, birds have a habit of seeking shelter in the estuary?

​Whatever the reason, it does seem that we've had a bit of an influx of Caspian and Yellow-legged Gulls, the former being particularly welcome as it's been a pretty lean winter for the species so far. Interestingly I noticed more Lesser Black-backs on the tip than I have done for a couple of months, so perhaps these have moved in and brought some Yellow-legs with them.

What's also stark is the strikingly high proportion of second-winters of each species, which reflects last winter's high numbers of first-year birds – and is also a hint that the 2019 breeding season was poor (we know that seems to have been the case for Caspians at least, judging by comments from ringers in Germany and Poland).

I started at Rainham, where I quickly racked up five Caspians on the tip within an hour, although viewing was a little tricky due to the incessant south-westerly wind. These comprised an adult I didn't recognise, two second-winters (one new, another fairly unimpressive bird that had been seen by Rich and Dante on 10 December) and a couple of first-winters, again one being new for me. This fresh bird was good value; it was great to watch it 'albatrossing' and throwing its weight around on the tip, and it should be quite easy to track it by its distinctive replaced central tail feather.

It seemed like a lot of birds were already going onto the river by 11 am, so I headed around the south side to Erith Pier, where Dante and Rich had arrived a short while before. They'd already had a good start to the day with at least one 3cy Caspian, the returning Caspian x Herring 'X90A' and double figures of Yellow-leged Gulls.

The first bit of interest to arrive at the famous pier was a 2cy Caspian x Herring Gull – a bird with plenty of covert moult but far too much in the way of Herring influence for it to sneak through as a pure Casp, for example the head and bill, short wings and overall uniform-ness. It was also a really ugly bird!

While we were watching this, two different first-winter Caspians came into the melee, allowing some close comparisons with the 'mule'. The first flew circled overhead a few times, looking fairly disinterested, before heading off downriver. The second, however, got stuck in to the offerings, gave decent views and was calling regularly.

Then an adult Mediterranean Gull arrived, the first I have seen in London since the summer (which in itself was a very poor season for the species, with just a few seen). Meds are pretty scarce in London in winter so it was welcome, even though it had a nasty leg break. Perhaps this limb will fall off at some point.

A third Caspian Gull then appeared, this one a familiar bird that I'd first seen with Dante at Rainham back in early December. It's a distinctive individual, with an obvious pale tip to the lower manible and a noticeable pale skirting to the coverts, creating a 'double wingbar' impression.

Annoyingly, what would have been the bird of the day flew straight through and didn't stop – a big and imposing second-winter, with superb plumage (look at those p10 mirrors!) ...

We then had a quick look in at Crayford, where there was a good turnover of birds and a couple of Caspian Gulls – single second and third-winters – dropped in to bathe on Jolly Farmers. A good end to a good day.