Caspian Gull | uaebirding

Caspian Gull Larus cachinnans
Uncommon to possibly locally fairly common passage migrant and winter visitor.
Confusion with Steppe Gull evident.

From the excellent 'Birds of the Middle East' app for iPhone & Android:

Caspian Gull (adult):

The palest of the large gulls in the UAE, as pale as an European Herring Gull.
White mirrors on P10 and P9.

Has the most white in wing-tips, with a large white tongue on the inner web of P10 (outermost primary); often with large all-white tip.
Black wingtip extends strongly to P5.

Grey tongues protrude fairly deep into more restricted black on primaries.

Underside of flight feathers grey against grey coverts.
Flat forehead can be diagnostic, with an angular rear crown.

Adult winter with seemingly unstreaked head; very discreet streaking around eye and on crown at very close range. Steppe Gull with streaking to February.

Eyes: 75% of birds with a dark 'bullet-hole' eye. 25% of birds with pale eyes.

Adult winter; bill with red spot restricted to lower mandible, can have small black subterminal band, esp. on upper mandible

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Proposed Caspian Gull photos from the UAE: click here

Feel free to email me if you do not agree on the ID.

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Note:
- unstreaked head at the end of January (Steppe Gull should have streaks)
- flat forehead

- P10 all white, with small black smudge
- P9 with a large white spot
- grey tongues protrude deep into the black on primaries

- strong black tips to primaries, all the way to P5

- pale eyes (25% of birds have this)