Birtsas, P., & Papageorgiou, N. (?????.).  (2006).  Nest Site Characteristics of Black-Crowned Night Heron (Nycticorax nycticorax) in Lake Kerkini, Greece. ??? 3° ???????? ????????? ??????????? ????????? & ????????? ?????????? ????????? <<????????? ??? ????????? ??? ???????????????>>. ????????????? ??? 16-19 ?????????, ??.?.?.?.?.?.?. «??????? ???????», ?????????????????, 45110, ????????.: ??????????? ??? ????????????? ?????????.