Diet of the common kestrel <em>Falco tinnunculus</em> in east Cork and west Waterford: an insight into the dynamics of invasive mammal species

Abstract

The common kestrel Falco tinnunculus Linnaeus is chiefly a predator of small mammals, and breeding density and success often fluctuate in tandem with cyclic population changes of Microtus voles and the common shrew Sorex araneus Linnaeus. Ireland traditionally had four prey species to support its predatory birds and mammals—field mouse Apodemus sylvaticus (Linnaeus), house mouse Mus domesticus (Linnaeus), brown rat Rattus norvegicus (Berkenhout) and pygmy shrew Sorex minutus Linnaeus (indigenous species)—but the arrival of bank vole Myodes glareolus (Schreber) and greater white-toothed shrew Crocidura russula (Hermann) (invasive species) has taken the number to six. The wider range of prey species may positively affect birds of prey, but the impact of invasive species on the ecology of indigenous species may be negative, especially on field mice and pygmy shrews. Negative effects on indigenous species have been shown to be strong to the point of bringing about species replacement in some habitats, with no pygmy shrews present where both invasive species (bank voles and greater white-toothed shrews) were present.