Locality: Porth Killier bay, St.Agnes, Isles of Scilly - 26th October 2007.
Age & sex:1st winter – possibly a small female.

The following are slightly edited extracts from the rarities report, recently submitted to the Isles of Scilly Records Panel. Also a selection of the digi-scoped images - untouched and not enhanced in any way.

Account - Observers - TD/RMRJ/RWK/DAN

Myself and three other birding friends had spent the late morning and afternoon of the day of 26th October 2007 on the island of St.Agnes. Having already seen a Rose-breasted Grosbeak on St.Agnes earlier in the week and a Dusky Warbler being discovered in the small fields around Troytown on Thursday (25th) evening, St.Agnes seemed to be a good place to spend our last day. We had been working the Porth Killier bay area in search of roosting waders. We were also wandering back towards the quay in order to catch the late afternoon boat back to St.Mary’s.

It was around 4pm that I noticed a medium sized gull flying into Porth Killier bay accompanied by a small number of Black-headed Gulls. The flock of gulls flew by and I casually called out 1st winter Common Gull. As I watched the bird I noticed a pale secondary panel in the wing and also noted a tail band but paid little more attention to the bird. We continued to examine the waders and noted a good variety including Whimbrel, Grey Plover and Knot. As time was pressing on, we started to walk around the Porth Killier bay joining the main path that heads off towards the quay. It was about 1610hrs that our attention was redirected to the “Common Gull” and what attracted our attention even more, was a casual comment made by an unknown passing observer and his partner, “Why is the gull amongst the Black-headed Gulls not a Ring-billed Gull” followed by “I am not sure, as it is sometime since I have seen a 1st winter”.

Ring-billed Gull started to enter my mind, especially as I had previously made comment to myself that the bird had a pale secondary wing panel. We continued to comment amongst ourselves that the bird was indeed very pale mantled but some felt that the bill was too small and neat for Ring-billed Gull. I made comment that the bird was very heavily blotched on the head, nape and neck for Common Gull, the mantle was a very pale grey and that the bird was “long-winged” and didn’t have the gentle expression of a Common Gull. I decided to take a sequence of Digi-scoped Images (attached) and during this time something disturbed the small flock of gulls and they drifted across to the far side of the bay. At this point a comment was made that the head and bill looked better at a distance for Ring-billed Gull and we all made comment to the bill pattern reminding us of a first winter Glaucous Gull. Time was now really pressing, and we reluctantly left the bird in the bay and promptly marched off to the quay, arriving just in time for the boat.

On arrival back at out flat on St.Mary’s,
we began to see many features of 1st winter Ring-billed Gull from my photos:
the pale grey mantle, especially compared to the Black-headed Gulls; a heavily blotched head, neck and nape that extending around to the flanks as crescents or chevrons, similar in shape to the markings on the mantle. For me the best features that stood out for 1st winter Ring-billed Gull were the pale fringes to the tertials, pale grey mantle clearly showing white tips to the scapulars and dark sub-terminal crescents or anchors on the mantle. (This feature is not normally present on 1st winter Common Gulls, which normally show a plain and uniform mantle).

On closer inspection of the photos the bill appeared to be the right colour, a pinkish base with a good black tip, reminiscent of 1st winter Glaucous Gull and also appeared less delicate than in the field. The leg colour was never determined.
Due to insufficient reference to RBG,
I decided to make a more detailed inspection of the bird once I got back home. I was even more convinced that our bird was a 1st winter RBG when I checked out the “The Gulls of Europe, Asia & North America” and also some old photos that I had taken of a well watched second winter bird on the Hale Estuary, Cornwall many years ago.

I decided to seek further advice from a well known Derbyshire birder whom I consider to be very reliable on gull identification. I value his advice and expertise and was sure that he would be able to make valuable comments either way.

Very shortly after receiving my email, he answered back and confirmed my suspicions and agreed that this indeed was a first winter Ring-billed Gull.

He commented that many 1st winter Common Gulls could match individual features that are detailed but the combination of all the features is pretty conclusive for Ring-billed Gull.