During a visit to the isle of Terschelling, it was amazing to see 3 Herring Gulls that were fitted with Russian color rings. Two of them were even fitted with a geolocator!
3 December 2016, Terschelling, the Netherlands.
Adult Herring Gull Black KUF7 plus white ring with geolocator:
Adult Herring Gull Black KUF5 plus green ring with geolocator:
Adult Herring Gull White KY35:
Here a video of the gulls fitted with a geolocator: