Friday, 20 February 2015

NGB Gullfest - madness in the Midlands

This blog post probably should have come a lot sooner, but I think we've all only just got over the mental fatigue that comes with trying to get your head around gulls! Anyway, on 13th December 2014, five NGBs embarked on a great day out in Staffordshire which was dubbed the 'NGB Gullfest'.

Matt Bruce, Zac Hinchcliffe, Espen Squinty-Ashman, Craig Reed and James Grundy started the day off at Chasewater Reservoir near Lichfield. It was a stunning winter's day without a breath of wind, single cloud and there was a lovely frost. Starting out the day in mid-morning didn't exactly mean there were thousands of gulls at Chasewater, but we had a look around for one of the few Willow Tits which frequent the country park, but sadly we weren't able to find any.

Left-Right - Espen, Craig, Matt and James scanning the far bank to get Moorhen on the daylist (no really...)

We moved onto Stubber's Green which is a green with a small lake located only a mile or so to the south of Chasewater where quite a lot of gulls go to bathe and loaf during the day prior to thinking about leaving for the roost. Within a very quick scan Craig managed to pick up a rather lovely adult Yellow-legged Gull. Being from up north, I'm keen to get as much information as possible from 'possible' Yellow-legged Gulls to 100% rule out hybrid. This meant watching it for a long time before it eventually stretched its wing and revealed its spot on wing formula.

adult Yellow-legged Gull with even a black spot on p4. Spot on!

In terms of species, there wasn't a huge diversity within the rest of the gulls, but we did spend a while trying to read a few colour-rings. As far as I'm aware we managed to successfully read all four of the ringed birds we came across. These included:
Danish Black-headed Gull, a Polish Black-headed Gull and two Herring Gulls ringed on the Severn Estuary.
Details are yet to come back on exact ringing dates, but this does show the importance of ring-reading and also ringing itself. It's great to know where some unassuming Black-headed Gulls have come from. They don't all just stay at your local McDonalds (other fast food restaurants/Black-headed Gull outlets are available) munching on chips!

There was another site that Craig took us to, but there was about four gulls on it, so it's hardly worth a mention...let's be honest!

Right! Onto the important bit... The gull roost! We arrived at Chasewater with about an hour to go before sunset. It was a lovely evening and that wind has stayed off all day making for superb viewing conditions. One of the first birds we got onto appeared to be the same adult Yellow-legged Gull from Stubber's Green as it had a distinctive squashed face.

Presumably the same Yellow-legged Gull as at Stubber's Green with very similar wing pattern and face.

It wasn't long before James Grundy uttered the words that have haunted my dreams since December 13th and probably will for some time to come! He said "Guys...I think I've got a Ring-billed Gull...."
Understandably, we were all taken back a little and thought it must be a very heavily ring-billed Common Gull. I then looked through James's scope expecting said Common Gull and then I saw it. BLIMEY! It looked spot on! The bill was broad, yellow, with a very thick black ring. The eye was pale, the mantle was pale and a similar shade to the Herrings around it. The wings looked long and there was limited white mirrors to the outer primaries. It looked absolutely spot on! What a cracking find from the NGB.

It doesn't look bad does it....

Craig then reminded us that we had better be completely sure it wasn't the Ring-billed Gull x Lesser Black-backed Gull hybrid from 2012 that was seen reasonably nearby at Priorslee Lake. I remember seeing photos of that bird and I remember how much it didn't look like a Ring-billed Gull and very much like it LBBG it did. I was completely confident it was not that bird. What I hadn't realised was that there was a second hybrid and it looked very much like a Ring-billed Gull with the exception of a slightly dodgy wing formula and darker mantle.

Note the broad tertial crescent and slightly darker mantle shade here

The huge elation of seeing a new species was ever so slightly wearing off as I was shown a photo of how 'perfect' the second hybrid looked. Scrutinising our bird, we noticed that it was ever so slightly darker than the surrounding Herring Gulls and noticeably darker than the surround Black-headed Gulls. This was a little worrying, but it was certainly not as dark as any of the Lesser Black-backed Gulls and it didn't appear to be as dark as the Common Gulls reasonably close by. We, aside from Mr Cynic Espen, we were all still confident it was different to the hybrid and a pure bird. All gulls are variable, so mantle shade doesn't always follow the rules, but unfortunately for us, Ring-billed Gull is regarded as one of the least variable gulls in the world!

Craig's photo showing how it compared with the surrounding Lessers (It mainly associated with Lessers, so perhaps that should've set alarm bells ringing?)

Facing away shows how almost YLG in tone it was

We decided to get some photos and video to send around to other birders that knew much more than us.

To begin with we got a couple of responses that said "Looks good, but something doesn't add up? Too dark, tertial crescent seems broad and the head streaking doesn't look right".

If we were going to go any further than this, we needed its finger print. This not only would help to confirm if it was pure RBG, but also whether or not it was the same bird as the hybrid from Priorslee. We'd been watching it for about twenty minutes and I was starting to run out of video camera battery. Luckily it started to bathe and I knew this was going to be the moment it would flap. I pressed record and after about ten seconds, I got the flap! It looked spot on! It also looked pretty different to the Priorslee bird so we were happy.

Upperwing bleeding through on the underwing wasn't a great feature. As I views this through my camera screen, I don't know how realistic this was.

Several photos of the open wing including a montage by Chris Batty showing the Priorslee hybrid (top), our bird (middle) and a pure Ring-billed Gull in Ireland (bottom). It's hardly much different to the pure bird, is it?

We consulted a lot of of experts and in a lot of the photos they were all pretty happy it was a Ring-billed Gull. When Matt and Craig went back the following monday and saw it again in more neutral light, it looked a lot darker, even prior to sunset and it was as dark as if not darker than Common Gull. We gave this further info to the experts and most did question their initial thoughts.

As the light started to disappear, the mantle shade started getting considerably darker. I know this isn't the most incredible scientific breakthrough in it got dark, the mantle got dark. What I mean by this is as the light faded, the shade of the bird got even darker than the surrounding Herrings and looked closer to LBBG in colour than Herring. That surely isn't right for RBG? We were happy we had gotten sufficient footage and documentation of the bird, so we decided to leave it and have a scan for other goodies in the flock before the light went even more.

If any of you know me personally, have read my personal blog or follow me on Twitter, you might have noticed I've been a bit obsessed with Caspian Gulls the last few years. Chasewater is renowned for Caspians, so I was certainly hopeful I would FINALLY see one. I scanned through the flock in front of us and nothing was jumping out at me or anyone else. Craig scanned a small bay to the far left and said "Oo, this looks interesting".

I recognised that "oo" straight away and frantically scanned the small bay to get on his interesting bird. "Black-head, Black-head, Herring, Herring, Black-head, Lesser and ............". And there it was! It stood out like a sore thumb! It was so pale headed, mantled and so long in the neck, head and wings!

I mean just look at that.....

CASPIAN GULL!!!! A stunning second winter bird. We all sprinted over to get better views and picked it up actively swimming around. I was recovering from a knee ligament injury at the time and I regretted that run a couple of hours later, but at the time I didn't even notice I was in agony! What a stunning bird with a wonderful face! I got a few record videoclips of it before moving onto just watching it. They say you should never meet your heroes, but after looking at so many photos of Caspian Gulls throughout the years, I was definitely not disappointed!

Elsewhere in the flock, we didn't manage to locate any 'white-wingers', but we had at least 7 adult Yellow-legged Gulls and we were able to scrutinise lots of immature large white-headed gulls which taught us quite a lot.

It was a really great day and not just because of the birds. The weather and the company was brilliant and we were all there for the same reason - to look at some superb birds!

P.S After consulting lots of experts and a couple of members going back for seconds, the general consensus now is that the gull was indeed the Ring-billed Gull x Lesser Black-backed Hybrid from 2012 (apparently gulls can change their wing pattern from year to year, particularly if they aren't fully adult. The 2012 bird was considered to possibly be sub-adult at the time)

-Zac Hinchcliffe
Zac is a Lancashire birder, ringer and aficionado of all things Cyanises, Larus and occasionally SyrphidaeZac is 22 and now works as a consultant ecologist after studying a Research Masters at Bangor University investigating Welsh Twite; adding a touch of science to his birding.

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