SLATY-BACKED GULL

We decided to go for the Slaty-backed gull (first for Britain) in Rainham marshes with Rob.

We arrived at Rainham marshes at 9:20,   we asked in visitor center if there has been any sighting of the gull but the answer was negitive ,  but We still decided to walked along the sea wall rob picked out 11 Avocets along the mud on the river,then dad saw this small falcon flying low over the mud flaps and we ID it as a Merlin a good year tick , we kept on walking towards serin mound where the gull has been sighted from on other days , there was 3 birdersthere scanning though a large roost of gull . but there was still no sign of the Slaty backed 

I walked abit further along the wall and still could'nt find the gull but then Rob and Dad started walking down and we got a closer view of the gull flock and the after about 10 minutes of scanning Rob picked out the Slaty backed gull and then we all got onto to it, and got a good view . we could not believe are luck a first for britain , it then flew of abit futher back and was picked out again by another birder the colouring on the back was very noticible .
other dirds to note were a flock of 40 linnets , wigeon, loads of goldfinches, and a kingfisher
After a good weekend of birding we decided to head home.