Sunday, 5 October 2014

Caspian Gull on the Adur (5 October 2014)

My ambition on checking the gulls on the Adur (at low tide, mainly for colour rings) has been to find a Caspian Gull, preferably a colour-ringed individual.  I've previously had a couple that I felt were but didn't feel I had got quite enough on to rule out a hybrid. Today's bird appears to me to be a classic.  According to the CR-birding web-site it appears to have been ringed in the Lausitz area of East Germany, inland near Polish border.  This is a mixed colony where Caspian Gull dominate although hybrids are possible so maybe a trait score is needed.  I'll post more when I find it out.

Today's low tide was mid afternoon and going after the tide had dropped seems a good time to avoid bait-diggers.  A reasonable number of gulls were spread along the Adur by the airport and I went down the west bank to have the sun behind me.  I soon saw a North Thames Herring Gull although it took a while to read the ring (FZ2T).  Then I noticed a very white headed gull which started ringing alarm bells.  That it had a green ring on added to my excitement but although I could read 3 letters it was standing in a dip and I felt it had a 4th.  I changed position to try and get a side view but it twisted to remain head on.  Eventually I got excellent views (and read the 4th letter on the ring).  I phoned Paul James, the only local I had a number for and continued watching and photographing the bird.  Fortunately Paul and Briget arrived before the bird flew off. 

an interesting very white headed gull (although this image is a bit over-exposed) with a green colour ring, my pulse quickened ...
first views of XNEK were not the most helpful wit the X being obscured and side and rear of the bird hidden
it looked very good for Caspian head on (note the very thin legs) but it seemed to take ages to get a view of its side when I felt my suspicions were confirmed.

Caspian Gull in flight
flight shot showing the white head and streaked neck shawl
the white head, grey mantle with darker feather centres, brown covers and black wings give the expected four-coloured effect.  Note also white thumbnail tips to dark tertials, long wings, small forward placed eye and at this angle longish parallel sided bill (perhaps the one feature that I might have liked to be more obvious)
forward positioned small eye and snouty appearance showing well in this image

small head, sagging belly and 'Annaconda having swallowed Capybara' neck
a classic pose showing plumage features and sagging belly

a small bird compared to the nearby Herring Gull so presumably a male
the streaked neck shawl just about visible in this image
it looked pretty much a classic to me

Caspian Gull passing Greater Black-back with dead eel

flying off over Old Shoreham Road, presumably to roost, at 17:46, long wings and drooping bill evident
final shot showing pale underwing
I eventually found out it had come from Brandenburg, about 100 km SSE of Berlin and had travelled 1004km west

Walking back after it flew off I saw another North Thames Herring Gull (XT6T) while earlier I had seen a Kingfisher, a Wigeon and a Curlew on the same stretch of river.  In the morning Megan and I had a walk around Cissbury.  Lovely and clear (Portsmouth's Spinnaker Tower clearly visible) but few birds and migrants represented by 2 Swallows, a superb Tree Pipit, 3 Blackcaps and 8 Chiffchaffs.

Curlew on the Adur
North Thames Herring Gull FZ2T.  Not one I've seen before.
North Thames Herring Gull FZ2T, easier to read when side on
North Thames Herring Gull XT6T
Kingfisher on the Adur

Wigeon on the Adur

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