I know you are not in the USA and that is why I started my posting with, "Here in the USA…"
Even though sea gulls are protected in the US, they are still shot, poisoned, and trapped, since some people consider them a nuisance. But doing that is illegal, but those folks do not care, that is until they are caught, then it's "I'm sorry, I did not know…"
But I googled Switzerland and trying to find the facts concerning sea gull protection in Switzerland is difficult since I do not know the legal structure of your country. But from what I did find, you probably should not be flying your drone in any manner that might be construed to harassing the gulls…
Just saying; a word to the wise; don't take it as a personal attack; I am not your seagull…