More from my visit to RSPB Dungeness on the 27th Jan.
2nd Winter (2nd cycle) Caspian Gull in flight and then coming to join the roosting flock to join another two 1st winter (1st cycle) Caspians.
A morning and early afternoon of almost constant heavy rainfall which meant I didn't venture out until mid afternoon. I decided to head to the RSPB reserve and check the gull roost on Burrowes. Over the past few days the number of roosting Great Black-backed gulls has gradually reduced or the later tide time change is affecting the number of visiting gulls that i'm seeing. A few days ago there were at least 1,000 Great Black-backed Gulls coming onto Burrowes to roost and bathe, today maybe 300 whilst I was there but still some good views opportunities to look through and check for Yellow-legged and Caspian Gulls.
I was also trying out some different camera settings in the relatively gloomy light conditions.
The Caspian Gull didn't hang around and flew off after finishing bathing.
An early afternoon visit to Hanson Hide on the RSPB Reserve led to a new birding experience of two Bitterns in view at the same time. A scan from the hide along an adjacent reedbed edge revealed a Bittern stood at the edge of the reeds seemingly warming itself up in the sunshine against the cold north-easterly gusty wind. What I didn't realise was that a second Bittern was also in the reeds just to the right of the one I was focused on. Bitterns are highly territorial and it looks to me like these two Bitterns were potentially having a bit of a tiff.
A quick visit to the Dungeness RSPB reserve in a bitterly cold north-easterly wind. The juvenile Great Northern Diver was still present at the north end of Burrowes Pit, five Avocets were standing on one of the submerged islands and three Goldeneye were feeding. Initially not many gulls appeared to be amongst the masses of Cormorants but gradually more started to arrive to roost, preen and bathe.
In recent weeks there has been some great gull watching at Burrowes Pit on the RSPB Reserve and many great photos on Martins Blog PLODDINGBIRDER have incentivised a few visiting birders to start looking for Caspian and Yellow-legged Gulls. The recent totals of these two species (to date at Least 20 Caspian Gulls and nine Yellow-legged Gulls) mainly using Burrowes Pit, has given plenty of opportunities to try and identify various ages of Caspian and Yellow-legged Gull against the commoner species of Great and Lesser Black-backed and Herring Gulls.
I'm still a relative newcomer in respect of having the opportunity to sit and look through gulls and whilst many birders ignore gulls as too difficult, they are a fun and rewarding group on which to hone your identification skills. In this blog post and maybe a couple of other posts, i've tried to provide a little bit of information on identification features for Caspian and Yellow-legged Gull, mainly for my own benefit to understand if i'm getting it right or wrong along with a chance to compare and use the identification literature against my photos. So, if you want to, please feel free to comment on my id attempts and associated reasoning.
December 8th
In the shot below, there is an adult Caspian Gull which is just taking off and three Yellow-legged Gulls, a 3CY flying, a 2CY to the left of the adult Caspian Gull and an adult (third gull in from the right that is partially obscured).
The adult Caspian Gull (before it took off), whilst showing the beady dark eye and lovely smallish pure white rounded head and long/pointed parallel billed head profile, has pale yellowish legs.
The yellowish looking legs confused me until I read much later that adults have pale yellow legs (in summer). Luckily other features to aid identification of adult Caspian Gull became more obvious when it flew. 
Primary 10 (P10) shows a long white tongue with very little black near the tip. Whilst this feather looks old, it is a typical adult feature. On the upperwing you can only just make out a narrow portion of the tongue but on the underwing, whilst still only a narrow section is visible you can see that it is long and whitish. There are also long white mirrors on P10 and P9, something which adult Yellow-legged Gulls don't show on P9. 
Another feature to support adult Caspian Gull is the presence of a tick mark on P4. In this photo the features on P10 and P9 are obscured. I reckon there is another possible feature in that the underwing is very pale with little contrast between the primaries, secondaries and underwing coverts. So, despite thinking this adult gull has dull yellow legs and pinkish feet, other features are good for supporting adult Caspian Gull. 
Adult Caspian Gull (left) and a 2CY Yellow-legged Gull (right)I stayed on the RSPB reserve in Makepeace hide (now called Shirley Coward) until dark watching the large gulls coming on to Burrowes pit to roost. I was hoping to see some gulls with rings but despite over c.1,300 large gulls roosting on the islands in front of Makepeace hide and Firth viewpoint I didn't pick up any rings. To see so many gulls flying in and settling was great and I was just about to get a phone photo of the spectacle when a juv Grey Heron decide to land amongst them causing many to fly off!
Whilst I was wandering towards the Pines at ARC, Dungeness RSPB, a message came through the Stephen Message had found a Pallas's Warbler at Dengemarsh Gulley. I returned to my car and it wasn't long before I was walking down the badly pot-holed track towards the gulley having decided not to risk driving my car down the track. Martin, Owen and Colin were already there when I arrived and it wasn't long before I was also watching this superb green and stripey warbler. Superb find by Stephen and thanks to Owen for giving me a lift back to my car.
A productive early morning wander around the north east side of the Long Pits recorded: 6 Whinchats, 2 Spotted Flycatchers, 23 Willow Warblers, 25 Chiffchaffs, 2 Reed Warblers, 2 Sedge Warblers, 43 Blackcaps, 5 Reed Buntings, 6 Yellow Wagtails, 2 Grey Wagtails, 24 Robins, 2 Wheatears, a Green Woodpecker, 13 Whitethroats and 6 Lesser Whitethroats.
Martin who was at Jury's Gap messaged that 15 Glossy Ibis were heading towards the Point over the RSPB Reserve. I'd just returned to my car at the top of the Long Pits and was able to get some height as Jacob radioed that they were over the Trapping Area. There were 14 over the Trapping Area so bizarrely we had lost one in-between.
