Arriving at Minsmere RSPB at about 8.15 am on 27 March, I walked to East Hide. A Sand Martin flew across the North Bank, and from the hide the usual congregation of large gulls and Black-tailed Godwits attracted my attention.
Among the horde, it was nice to see both a first- and a second-winter Caspian Gull and at least three Yellow-leggeds. It was not long before I found a strangely distinct, paler mantled gull among a group of Great Black-backs and Herrings, with soft and blotchy crescent-shaped streaking on the head (creating a vague hood) a dark eye and raspberry-pink legs. It was very distinctive and different enough to make me immediately think that it was a northern Pacific-Rim bird; although I had never seen adults of these, it seemed somehow familiar.
John Grant entered and, after I mentioned the gull to him, he also became rather 'taken' by it. For the next hour we observed it carefully, in between pointing out Caspian Gulls to those interested. I proposed to John that it might be a Vega Gull and we joked as to who would ring it out. I certainly was not yet prepared to disseminate news of a 'funny-looking' gull at Minsmere.
Initially, its comparative size — equal to the Herring Gulls around it and with a rather gawky shape to the head — with a quite rounded crown, gave it a look that reminded both of us of the photos of the Vega Gull in Ireland taken by Killian Mullarney (see Birdwatch 284: 8–9 and here). My knowledge of Pacific-Rim gulls is largely theoretical, but I knew this was not an ordinary Herring-type gull. The one element we had not seen well was the primary pattern; it spent most of its time hidden or sitting on the ground, but the underside of p10 visible on the far wing looked very white.
I was about to leave to meet my son, so I took a few distant photos and videos that I hoped would show the head shape and features, but I was quite concerned about its identity and also that others should see it. I rang Adam Rowlands, describing to him the obvious features and said I felt it was a Vega-type gull — even perhaps still growing its primaries. However, it was then that Adam suggested Thayer's Gull.
As part of the BBRC review of the Pitsea Thayer's (see Birdwatch 223: 52–53), one of the committee members had brought up that, at times, the two might look very similar, but I did not pick up on this until later. I also let David Fairhurst know, hoping that he might be able to see this bird. With familial duties calling, I cycled home with the bird still nagging at my mind as I went. I met my son Ben with my photos still in the camera inside my wife's car at the reserve.
I needed to check some references on the internet, and there was no doubting my first impression that the head shape looked like the images of Vega Gull in Ireland, though it wasn't identical — there was too much white in the primaries for it to be Vega. Next, I looked at the photos of the Irish and Spanish Thayer's Gulls on the Birding Frontiers website and the penny dropped in a most expletive-ridden manner.
By now it was late morning, and David Fairhurst had finally succumbed to temptation and was watching the bird when I rang him. We discussed that the plumage looked spot on for Thayer's but, like me, I think Dave was a little concerned about its size and head shape. I think David felt we had better put it out as something; I am not a fan of 'possible' or 'probable' sightings, so he texted it to Suffolk BINS (www.freewebs.com/suffolkbirding) as a gull showing characters of Vega Gull. Almost instantaneously, however, we had realised it was more likely a Thayer's. He had seen and videoed it in flight. We went through the primary pattern over the phone and then texted to BINS that it showed more characters of a Thayer's Gull.
Finally, I took Ben out for a drive and somehow we strangely ended up at Minsmere. Gathering my gear from Janet's car, we walked to West Hide, from which, looking into the light, you could see the bird asleep but viewing was not ideal. After 'flat-batting' a bit of questioning by those present, suddenly it took flight and... Wow! What had seemed quite a large gull on the ground seemed compact and smaller in flight, and more importantly the general wing pattern seemed great for thayeri. Superb!
There was a lot of excitement at that point and I got a text from Adam, who had also seen it take flight; he confirmed our impression of it being Thayer's, though there was still a little caution as we had yet to see a good photo that showed the precise wing pattern. As we walked round to South Hide you could see the bird from the path, though hidden; from the hide itself it was viewable head on.
I was mentally kicking myself that I had not sorted the bird's ID out earlier, but now that I was more confident it somehow seemed a lot easier. With some excellent sharper photos of the primary pattern taken by Craig Fulcher and Jeff Higgott, you could finally see the exact pattern on the wings and, like Adam, I felt it was absolutely spot-on for Thayer's. All of the features fell into place: the dark eye giving a quite gentle feel to the face; the pale creamy yellow base to the bill; the smudgy and ochre-brown head markings; the raspberry legs; and most importantly, the wing pattern.
What a day! It was a little fraught with having to leave the bird in the morning, and my initial sway towards Vega, but I simply had not expected how much alike Thayer's and Vega Gulls might be.
However, the correct identification had been a group effort, so I must say a big thanks to Adam and David for looking and for their part in the critical discussions over its ID. Finally, as I had not seen Thayer's before, the day had been a steep learning curve; it just goes to show there is always much to learn.