Barden

Chroicocephalus ridibundus, the Black-headed Gull in flight has such an amazing pattern of black, grey and white on its wing. Here you can see the obvious black on most of the primaries as viewed on the underwing, but the highly contrasting bright white of 90% of the underside of P10 and P9 apart from their jet black tips, with perhaps very small white patches on P8 and P7.

The rest of the underwing is mainly a contrasting dark grey, shading lighter towards the base of the wing, with maybe also a greyer patch nearer the front of the wing, but you generally also see a bright white front line to the front of the wing at the shoulder. 

The last two pictures are of the same bird, and its only in the first of these that you see a suspicion of the white flashes of P8 and P7. This could therefore be the angle of the feathers, with the white from above showing through when the feathers are opened or at a certain angle.

The upperwing is not the same pattern, with a much larger wingtip white triangle for a start, although there are a lot of general similarities.

To learn more, I'd better take lots more, and better, photos! This should enable me to recognise second winter patterns for example.

Here's an old photo from Cliffe - note how the primaries further in from P10 and P9, are both black and white!