This 1st calendar-year gull was marked with ring Y[PKNK] as pullus near ZB.Kozielno,Paczków, Poland (50°28'35.8''N, 16°58'54.2''E) on May 25, 2012. This is approximately 900 km east of Katwijk. After the Katwijk sighting, it was seen between Rennes and Nantes, France, on Januari 2, 2013. Although it was marked in a colony of Caspian Gulls, it is uncertain whether it is a 'pure' Caspian Gull.