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.
Highlights
Kleptoparasitism, the stealing of food from other individuals, has attracted much interest among ornithologists and many hundreds of papers on the topic exist
Byrkjedal et al (1997) described how Velvet Scoters Melanitta fusca that were digging for echinoderms in a sandy substrate thereby disturbed large numbers of polychaete worms that were exploited by Red-necked Grebes Podiceps grise gena
At all three sites the kleptoparasitism was recorded as number of attacks on the cormorants that were successful, i.e. resulted in the pelican stealing the fish from the cormorant
Summary
THE ASSOCIATION between Dalmatian Pelicans Pelecanus crispus and Great Cormorants Phalacrocorax carbo was studied at three Greek sites, Megali Prespa, Kerkini and Karla. 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 114 seconds. Pelicans mostly foraged singly or in small groups (mean 3.2 individuals) and often there were 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. Thirty-one attacks were very violent with the pelican holding the cormorant until it dropped its fish. K ÄLL ANDER (2020) | KLEPTOPAR ASITISM AND COMMENSALISM BET WEEN PELICANS AND CORMOR ANTS | ORNIS SVECICA 30: 5–12
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