Characteristics of soaring birds' spring migration over inland SE Bulgaria

by Shurulinkov Peter, Daskalova Girgina, Chakarov Nayden, Hristov Krassimir, Dyulgerova Silvia, Gocheva Yana, Cheshmedzhiev Svilen, Madzharov Minko, Dimchev Ivailo
Published 2011-01-01