They have taken adults of numerous larger water birds averaging over the expected prey weight of 2 kilograms , although (at least for wading birds such as stork) nestlings are most often preyed upon, including greylag goose (Anser anser), greater white-fronted goose (Anser albifrons), bean goose (Anser fabalis), bar-headed goose (Anser indicus), knob-billed duck (Sarkidiornis melanotos), common crane (Grus grus), great cormorant (Phalacrocorax carbo), white stork and black stork (Ciconia nigra).