Wednesday, 24 August 2011

1cy Yellow-legged Gull

I'm a strong believer that Yellow-legged Gulls are one of the most misidentified species to occur in Britain and Ireland away from their strongholds in the southeast, even above species such as Black Kite and Honey Buzzard. Regularly we read about large (double-figure) counts across much of the country in winter gull roosts, but should they really be that common through the winter away from the southeast?

Well, based upon my experience, probably not. Although it may be because of our geographical location in north Cambridgeshire, we tend to get as many Caspian Gulls in winter than Yellow-leggeds - i.e., not many. Away from the southeast, Yellow-legged Gulls are a bird of the summer, with the highest counts coming from June/July through to September, with numbers tailing off after that as they drift off south as winter advances. As I'm lucky to see one Yellow-legged Gull in the winter at Dogsthorpe, I do find it baffling when you see reports of 5, 10 or more from north Midlands reservoirs or the northwest. Perhaps I'm just not looking for michs in the winter but, in all honesty, it must be for a different reason - alot of these birds are being misidentified.

But the issue of Yellow-legged Gull misidentification is that it isn't exclusive to winter - it is happening right now, as I type this. Probably the most-commonly misidentified age class at the moment are this year's offspring, the 1cy birds. There seems to be a great number of people about at the moment who are simply re-writing juvenile gull identification. In the past week I have seen various sites/blogs/pages littered with juvenile Lesser Black-backed (and even Great Black-backed) Gulls that have been wrongly labelled as Yellow-legged Gulls. Many of these images depict fresh, heavily marked and darkish looking birds which, for anyone who truly knows 1cy Yellow-legged Gulls well will testify, is not the case with these birds by mid-August. Instead, Yellow-legged Gulls (as they were born and fledged perhaps a month or more earlier than British-breeding large gulls) are well into their moult to first-winter plumage right now. They are particularly striking, and are already much paler than they were a month or so ago. Claiming fresh juvenile Yellow-legged Gulls right now is fraught with danger as the vast majority of birds are well into their moult. The classic example I use is of this bird, photographed by Dick Newell in late August some years ago:

To compare, here is a 'real' juvenile Yellow-legged Gull from over a month ago - note how pale it already was by mid-July:

And below is a 1cy bird I had today at Dogsthorpe Tip. Although not as advanced as the very striking bird in Dick's photos above, it clearly illustrates what people should be looking for in a 'juvenile' Yellow-legged Gull in mid to late August - a bird that, for all intents and purposes, looks more like a first-winter than a true juvenile. Note the extensive scapular moult with lots of second-generation scaps with the classic dark anchor shape on them, note how the head and underparts have already become so pale that they are predominately white, and also note the undertail - virtually lacking any dark markings/barring so typical of juvenile Lesser Black-backed and Herring Gulls. The coverts on this bird below are also still in pretty good condition; alot of michahellis right now have much more worn-looking coverts:

Although there is admittedly considerable variation in large white-headed gulls (and I concede some michs won't be quite so advanced right now), I would hope these thoughts are worth pondering before claiming the next juvenile Yellow-legged Gull. Any 1cy bird that still looks fresh at this time of year simply won't be a michahellis, and thus likely a Lesser Black-back.

I'm off on holiday for a couple of weeks around Europe and will be returning on 8th September. See you all then for more larid action, I guess.

Monday, 22 August 2011

More Caspian Gulls, 22nd August

The only real success I seem to be having in local birding currently is on the tips and pits east of Peterborough, scouring the large gulls for a bit of cachinnans action. No gulls at Dogsthorpe today due to disturbance (perhaps the falconers had been back). Tanholt however was bustling, and there was plenty of turnover on the pit by the footpath - all in all, must have been 750 or so large gulls. Despite this, Mike Weedon, Will Bowell and I couldn't pick up anything amongst the birds regularly coming to bathe on the pit. So we headed round to the tip, where I soon picked up a couple of Caspian Gulls - the 2cy bird below, and a brief adult:

Views weren't exactly ideal on the tip today, viewing through the fence with alot of heat haze (as you can probably tell from the above). So we were pretty delighted when most of the gulls were flushed off the tip and ended up flying back on to the pit. Needless to say, the 2cy Caspian showed very well for a few minutes:

No sign of the adult though; guess it was still on the tip. The only other gull of note was this 2cy Yellow-legged, looking slightly odd and dumpy without fully-grown primaries:

I've now had 4 Caspian Gulls in Peterborough in the past week. They are evidently on the move.

Saturday, 20 August 2011

Juvenile Caspian still

The juvenile Caspian Gull was still at Dogsthorpe Tip this afternoon, although was quite flighty and soon drifted off over the tip and out of view. A couple more images from today; still not quite got the shots I'm after:

Not alot else going on at Dogsthorpe - a lack of tipping to blame, as is tradition on Saturday afternoons. So I headed round to Tanholt, where the new tip was full of gulls (500+). The only thing I could muster however was this already pale and rather advanced 1st-winter Yellow-legged Gull (excuse shit shot):

Thursday, 18 August 2011

Another slice of the cachinnans pie

Returned to Dogsthorpe Tip today with John Saunders in an attempt to relocate yesterday's juvenile Caspian Gull and hopefully show him the ropes with a few immature YLGs. The weather was very disappointing, being cold and rainy throughout the three hours I spent on site. Nevertheless, within an hour I had located another Caspian Gull - this one being a massive 3cy bird looking for all intents and purposes like a 3rd-winter. However, it was still moulting it's primaries and one or two other bits looked like they were yet to be replaced. Big, bulky bird with a huge conk - must be a male:

In the third (open wing) shot you can also see the white spot on the old P10 feather - a classic feature of 2nd-winter Caspian Gull if any confirmation was really needed.
In addition to this, yesterday's juvenile dropped back in mid-afternoon for 10 minutes or so allowing John some nice views to compare the bird to the surrounding juvenile Herring and Lesser Black-backed Gulls, as well as the couple of juvenile/1st-winter Yellow-legged Gulls we had observed earlier.

Despite the rain, a most rewarding afternoon.

Wednesday, 17 August 2011

Juvenile Caspian Gull

Fresh juvenile Caspian Gulls are a pretty rare sight in Britain - most 1cy birds appear a little later on when they have undertaken quite a bit of moult. Today (17th), I had a stunning juvenile at my local gull mecca of Dogsthorpe Tip, Cambridgeshire. I've put a few photos below - click for larger versions:

I think this is probably only the second juvenile I've seen, and definitely the freshest. Even at such a young age, a juvenile Caspian Gull is a wonderfully striking beast, as the images above illustrate.
In addition to the obvious structural features - ridiculously long legs, long parallel bill and long body giving a gangly, rangey appearance - the plumage is most striking. At rest, the remarkably pale (white) underparts are immediately apparent, particularly when viewed head-on. The tertials are plain and dark. In the final image (a composite of several videograbs), the underwing and upperwing patterns can be seen - unlike other juvenile gulls, the underwing is virtually white, even this early in the season. Note also the pale window in the inner primaries. The upperwing has a distinct and striking dark secondary bar. Although it can't be seen well, the tail possesses a dark and sharply-demarcated black band at the tip, although is predominately otherwise white with very limited flecking.

Brilliant bird!