• Journal of Ecology and Environment
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• v.29 no.6
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• pp.545-550
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• 2006

Ten supernormal clutches of little terns Sterna albifrons and seven clutches having mixed eggs by little terns and kentish plovers Charadrius alexandrinus were recorded during the breeding seasons of 2003$\sim$2005 at Ganwol lake, Hongsung-gun, Chungcheongnam-do, Korea. The frequency of egg retrieval by Little Terns was higher after the second egg laying regardless of the clutch size and incubation stage. The frequency of egg retrieval was high at all incubation stage. When experimental eggs were placed within 15 cm from the nests, the percentage of egg retrieval was highest (almost 100%). However the percentage dropped rapidly over 35$\sim$55 cm range and finally to zero at 60 cm distance. Little terns retrieved all kinds of eggs set near their nests regardless of its kind or size. This study suggests that egg retrieval by little terns may be a source of the nest with supernormal and mixed egg clutch observed in this species.