Analysis of the diet of Daubenton's bat Myotis daubentonii in Ireland

The diet of Daubenton's bat Myotis daubentonii (Kuhl 1817), which takes prey by aerial hawking and from the surface of water, was investigated by analysis of faeces collected in summer at 7 roosts, all close to rivers in pastoral land, in three widely-separated districts in Ireland. Forty-seven categories of arthropod prey were identified; several were insect taxa found in and around water. Most categories were recovered at most roosts, but mainly in small amounts. The main categories were the same throughout, accounting for 82% of the diet by percentage frequency in droppings for pooled data: Chironomidae/Ceratopogonidae 24% (adults 14%, preadult stages 10%), other nematoceran Diptera 21%, other Diptera 10%, and Trichoptera 26% (adults 20%, preadult 6%). A quarter of the prey had evidently been obtained from the water's surface (eg aquatic insects, their larvae and pupae). Although consumption of several food items varied significantly by month at one or more roosts, little of such variation was consistent between roosts.