The predation of Tern chicks by sheep

Abstract

Between 1973 and 1980, sheep ate parts of at least 680 live Arctic Tern chicks and at least 10 Arctic Skua chicks on Foula. This predation was almost completely confined to the dry heath habitat in the southeast corner of Foula. Characteristically, the sheep bit off one or both legs or wings, or more rarely the head. Three different sheep were observed eating chicks, but the habit is probably widespread among sheep on that part of the island. It seems probable that sheep make up nutrient deficiencies by eating chicks. Although up to 8% of chicks were eaten by sheep, losses were low compared with egg desertion and chick starvation, but predation by sheep may have contributed to terns deserting this colony in favour of areas away from sheep.