The caspian gull was a fairly subtle bird. Size-wise only a fraction larger than herring gull but proportionally smaller head and noticeably slimmer, parallel-sided bill with a greenish-toned base. The yellow was duller, less orangey than similar aged herrings and there was a nice red gonys spot. The legs were an insipid grey-pink but it never stood out of the water so judging length wasn't possible. It was slope-backed which meant its primary tips dipped in the water and it lacked any tertial step. The upperparts were appreciably darker than herrings but perhaps not as dark as yellow-legged gull. It was quite proud chested when stood relaxed and its eye was often a mere pin-prick and dark though through Doug's more powerful scope it appeared dark amber. A long wait ensued before the all important primary tips were seen but on the closed wing the underside of the longest primaries looked extensively white. Once seen the outer primaries showed a lot of white with a wholly white tip to p10 visible in the second photo. The bird flew out to see around 1610.