|ring area||Croatia, Zagreb|
|observations||1710, of which 1336 are captures|
|ringed in||2021 to 2022|
We started this ringing project in 2021. Most of the Black-headed Gulls are ringed in the winter time on the Jakuševec rubbish tip in Zagreb, Croatia. Some are also ringed on other rubbish tips. A small number is ringed on breeding colonies. We use yellow rings with a 5 alphanumeric code, starting with an S.