this morning I had an enjoyable gull-watching session in a little lake here in Northern Italy with at least 20 Caspian Gulls and 7 Herring Gulls among 120+ large white headed gulls...
The most interesting bird was a ringed one...I'm already sure it comes from Poland but am less sure about his identity
It had a clearly pale mantle (ok for both herring and caspian), very pale eye (herring) and quite pale eye-ring (could have been paler in a herring), P10 all white (ok for both), I think I can see a very little black spot on P5 (better for herring), very short (herring) and yellow (not a great problem for both) legs, a quite heavy bill (not too slim for a herring nor too heavy for a caspian).
I don't like very much the head shape for a Herring, it doesn't scream Herring to me, but I may be wrong...
In the end, if I should bet one pound on a species I would say a 'yellow-legged' Herring gull...but something doesn't persuade me till the end and the hybrid option is disturbing my thoughts .
I will soon get the response from the ring but I'd like to hear some opinion from you!!