Invasive alien Coypu (Myocastor coypus) as a prey of the native predator Eurasian Eagle Owl (Bubo bubo) in Bulgaria

Incorporation of the invasive alien species into the food web by native predators is important both for managing the invasion and for predicting potential predator problems from measures taken against the invasive population. The present study of the Eurasian Eagle Owl ( Bubo bubo ) diet in the area designated as the initial centre for the introduction of the invasive Coypu ( Myocastor coypus ) in Bulgaria provided new data on the spread and reproduction of the invader. The small overlap in the distribution of the predator and the invader accounted for the small number of owl pairs with Coypu-containing diets. The long-term study confirmed the hunting of young Coypu by Eurasian Eagle Owls only in years with a very wide food niche of the predator in the respective territory. The occurrence of Coypu in the food of the owl did not depend on the frequency of other wetland inhabitants in the annual diets. The Coypu was incidental prey (range 0.5 – 0.8% by prey number) most likely due to the low density of the invader in the area of cohabitation with the predator.