JanJ on Surfbirds mentioned that this bird looked more like a Larus barabensis (Steppe Gull) to him due to shorter bill and shorter looking legs. The bird in flight was in his opinion more difficult, since the primary pattern looked similar to Larus cachinnans Caspian Gull, since Steppe Gull usually has more black with shorter grey tongues. The bird is in moult with two renewed inner primaries with p10 (outermost) - p4 old. P4 lacks a dark mark altogether, which is not unusual in Steppe Gull although primary pattern in these might be more variable than is currently know. Taxonomy is an on-going process and currently barabensis (Steppe Gull) and Larus heuglini (Heuglin’s Gull) are subspecies of LBBG.
AbdulRahman Al-Sirhan from Kuwait kindly left a message below and mentioned it also looked more like a barabensis Steppe Gull as it has a darker mantle and the primary moult pattern fitted better for Steppe Gull rather than cachinnans Caspian Gull which at this time of year would have replaced 5 to 7 primaries. P10 at this time of year would show a negligible dark tip, this P10 is in line with Steppe Gull showing obvious dark tip. I would like to thank JanJ and AbdulRahman Al-Sirhan for their help with the identification of this bird.
Steppe Gull (adult)
Steppe Gull (adult)
Steppe Gull (adult)