Mediterranean gulls, Pennington Flash

I decided to walk along the canal this morning from the Common Lane footbridge towards the by-pass. Lots of red-eyed damselflies on the lilypads and suddenly I became aware of a "cow, cow, cow" call from overhead and looking up I saw a couple of Mediterranean gulls hawking for insects above me with a few black-headed gulls. I took a couple of photos before they disappeared and one of the birds is clearly a second summer, almost identical to the adult with a full black hood, but also with a few black markings on the tips of the primaries. Later they were both on the spit with a common sandpiper. A barnacle goose flew along the canal with a couple of greylags and four common terns were on the flash. 

In the afternoon the barnacle goose was on the flash with Canada's.