This 2nd calendar-year gull was marked with ring Y[PNSE] as pullus near ZB.Kozielno,Paczków, Poland (50°28'35.8''N, 16°58'54.2''E) on May 24, 2013. This is approximately 900 km east of Katwijk. Although it was marked in a colony of Caspian Gulls (Larus cachinnans), it is uncertain whether it is a 'pure' Caspian Gull.