The kleptoparasitic and commensal association of Dalmatian Pelicans Pelecanus crispus with Great Cormorants Phalacrocorax carbo

Abstract

The association between Dalmatian Pelicans Pelecanus crispus and Great Cormorants Phalacrocorax carbowas studied at three Greek sites, Megali Prespa, Kerkini and Karla.  At Prespa, the two species seemed to use each other mutually: pelicans benefited from fish that tried to escape from the cormorants by swimming towards the surface while cormorants used the pelicans as a cue to the presence of fish shoals. When a pelican flew towards a cormorant, other cormorants immediately flew there and dived instantly. The association usually was very brief lasting only a mean of circa 114 s. Pelicans mostly foraged singly or in small groups (mean 3.2 individuals) and often there were also few cormorants (median 6). Kleptoparasitism was recorded at all three sites, but at Kerkini and Karla, pelicans associated with the huge fishing flocks of cormorants and predominantly kleptoparasitized them. Around 20% of attacks were successful. Thirty-one attacks were very violent with the pelican holding the cormorant until it dropped its fish.