Peak summer gulling in East London

It's no word of a lie to say that this weekend's gulling exceeded all expectations. Having seen the first juvenile Caspian Gull of the year in London the previous Sunday, I had high hopes that we might snare another this time out. Dante, who is off to North Ronaldsay next week, was keen to get a final gull fix before heading north, so we made plans to give the gulls a good grilling on both Saturday and Sunday, taking in Rainham while the tip was still working on Saturday morning before moving round to Erith for the afternoon high tide, and then focusing on the latter again on Sunday. What neither of us expected was that we'd end up with a half-dozen of juvenile Casps, plus a few others of older ages ...

Saturday

​The weather was both bright and warm on arrival at Rainham at 8 am, yet despite the sometimes tricky conditions we managed four Caspian Gulls – a fine adult, which was only seen mid-river, a couple of third-calendar-year birds and, lastly, a big juvenile, which drifted off upriver on the incoming tide, tantalisingly right past Erith Pier ... which made me quite restless, much to Dante's annoyance (I think he'd have happily sat at Rainham all day). At that point, little did either of us know that we'd be seeing the same bird at considerably closer range later that afternoon! At least 80 Yellow-legged Gulls were tallied; most were juveniles, with adults the second-commonest age class (as you'd expect). Otherwise, the birding was quiet, with a migrant group of three Ringed Plovers and a Dunlin arriving high from the north just about the only other noteworthy sighting.

Gulls on the River Thames between Rainham and Erith, 3 August 2019

I'll cut to the chase without further ado. An hour on from leaving Rainham, some time after 2 pm, of our first offerings were dispatched into the Thames off Erith Pier and within seconds both Dante and I heard the classic hoarse call of a close Caspian Gull – we were thrilled to see that a strikingly big and pale juvenile had come straight in! It quickly became clear that it was the bird we'd seen distantly from the Rainham side a while earlier and it went on to spend much of the next few hours around the pier, occasionally making forays off downriver, but seemingly always returning. I have to say at the time that I felt it to be one of the better juvenile Casps I've seen and I would stick to that notion having reviewed the images. Richard Smith joined us while it was on show and needless to say he was thrilled to be able to walk up and start blasting off images of a Casp at point-blank range.

Initial views as the bird came in towards us to the melee, revealing its strikingly pale underparts.

A classic pose, illustrating just about everything you'd want to see in a textbook juvenile Casp ...

Another of the upperside, showing off the impressive bill and striking facial expression (note the obvious pale eyelids) against a typical East London backdrop.

Another view of the underwing.

Swimming around by the pier, showing off the diffusely marked greater coverts and revealing a bit of scapular moult.

We were made up with with one, so it was a pleasant surprise to double the tally a short while before packing up. Initially assumed to be the same bird as it came in from downriver, calling as it did so, 'juvenile two' then banked and revealed a clearly different tail pattern, being more barred than the first and being swarthier overall, with darker underparts. Furthermore, seeing it at rest revealed virtually no scapular moult and more extensive pale fringing to the upperwing coverts and tertials, perhaps suggesting some Herring ancestry. Nonetheless it was a real beast structurally, as good as the previous bird, and looked good in flight. It looks nice in Richard's much better selection of images, which you can see here.

The second juvenile of Saturday – compare with the photo above.

In flight, showing tail pattern and both the upperwing and underwing.

With some 5-600 large gulls present around the pier, plus the ever-present Yellow-legged Gulls numbering up to 30, most of which were juveniles, it was an excellent and memorable session to end what had been a productive Saturday – five different Caspian and in excess of 100 Yellow-legged Gulls is a result never to be sniffed at.

Sunday

Rich B arrived back from a family holiday in Portugal on Saturday evening and was champing at the bit to give Erith a go at high tide on Sunday. Needless to say, Dante and I were up for it and we all met up on the pier at midday. Once again, a juvenile Caspian appeared almost right away: one of the first birds that Rich clocked after chucking a slice of bread into the Thames was a rather stunning and slender female, with textbook structure and plumage. As I wrote here last week, juvenile gulls can be genuinely challenging in many instances, but sometimes they're refreshingly obvious – and this was definitely a case of the latter. Although initially proving a bit reluctant to show well, it stuck around all afternoon and eventually performed brilliantly  to the gathered 'crowd' of seven.

Bird one on Sunday was a beauty in all respects, possessing a striking tail pattern to offset the rest of its picture-perfect plumage.

A close-up of the underwing and tail on bird one.

Bird one (front) with a juvenile Yellow-legged Gull for comparison.

A second, much larger bird joined the melee mid-afternoon, proving particularly aggressive and vocal and surely a male on size. Initially I thought it was going to be the first bird from the previous day but, when it settled, it was quite obviously different, being much more advanced in terms of scapular moult and having more extensive pale patterning in the coverts and tertials, as well as a larger inner primary window. As I was lying down on the jetty trying to photograph the original Casp at the time, I didn't do too well for photos, but the below nonetheless give a decent feel for it.

Bird two comes into land off the jetty, exhibiting a fairly extensive inner primary window (with pale 'lozenges' on the outer webs of p2+3) and a nice tail band.

Bird two on the water, showing off its largely pale inner greater coverts, extensive moult in the scapulars and dopey impression.

As we were watching this bird, a third juvenile arrived to the party. We all felt that this was the least impressive of the three, although its gingery basal colour was both striking and attractive. It also had the muckiest underwing and was quite small and placid compared to the previous individual – on size and structure, we assume another female. It was also the only of the three to pose at close range on the jetty ... 

Bird three arrives and immediately gives off good Caspian vibes among the Herrings ...

Bird three in flight, showing a perfectly respectable inner primary window and tail band.

Finally, a Casp at close range on the jetty!

With excitement tailing off a little at Erith by late afternoon despite the continued presence of up to 30 Yellow-legged Gulls, Rich, Dante and I made the executive decision to head back in towards Central London. Rich is the most dedicated of us to a series of 'lesser' sites along the Thames, where lobbing out the odd bit of bread usually brings in a handful of gulls including regular Yellow-legged and – occasionally – a Caspian. He suggested a stop at King Henry's Wharf, one of said sites (in Woolwich), which quickly produced three juvenile Yellow-leggeds and then, amazingly, a juvenile Caspian came in calling; our fourth of the day! By this point the light had gone very dull and the bird probably looks darker in the following photos than it would have done had it been at Erith earlier in the day, but it was definitely a swarthier bird – albeit nonetheless looking fine for a fresh juvenile Casp. A great way to end a fantastic weekend of late summer gulling.

The King Henry's bird was big and imposing, even if mainly seen swimming around on the water.

Quite swarthy in flight with heavily barred tail, but a good underwing.

... and getting a bit fed up with the locals.