Breeding philopatry is well known in the Black-headed Gull (Chroicocephalus ridibundus). Using a capture-mark-recapture method, we studied if Black-headed Gulls show nest site tenacity and mate fidelity as well, and investigated if there are differences between a stable, and a newly established and fast-growing colony, as well as for differences between the center and edges of these colonies located in north-eastern Germany. We found a high level of nest site tenacity in the center of the stable colony on B?hmke Island, and lower degrees of nest site tenacity at the edge of the same colony and in the newly established and fast-growing colony on Riether Werder. Mate fidelity was very strong in all individuals which returned to their previous breeding place, regardless of the nest site location.