For a few years I have been tagging 20-25 individuals annually with Interrex GPS loggers in the Centre of Poland in the colonies in Vistula river. Mainly breading birds of Caspian, Yellow-legged and Mediterranean Gulls as well as Common Terns. Some GPS loggers have been providing high quality data continuously for more then 3 years. During the breeding season, summer months or on migration in more sunny locations, GPS loggers with activated boost functionality provides amazing volumes of data up to 600 data points generated even every 40 s. I have gathered absolutely fantastic history of number of breeding pairs and cases of tracking migration of Gulls to Western and South of Europe as well as Terns reaching south of Africa.