Analysis of Tawny Owl (<i>Strix Aluco</i>) Food Remains as a Tool for Long-Term Monitoring of Small Mammals

Abstract

Data on the Tawny Owl diet from the prey remains found in nestboxes after a breeding period in 1997–2004 in Kėdainiai district and in 1999–2003 in the Kamanos State Strict Nature Reserve are compared with the results of small mammal monitoring in these territories. The number of small mammal species found in the owl prey remains as well as their diversity was always greater, than that obtained by trapping. On average, 12.1 ± 0.9 species were recovered from prey remains in Kėdainiai, 11.3 ± 1.9. in Kamanos State Strict Nature Reserve, while the number of species trapped was 7.0 ± 0.6 and 6.8 ± 1.7 accordingly. Shannon.s H in prey remains was 2.62 ± 0.11 and 2.80 ± 0.14 vs. 1.97 ± 0.13 and 1.65 ± 0.33. It is obvious, that quite a lot of small mammals that are seldom trapped are found in owl prey. Analysis of prey remains may be used as a method for small mammal monitoring.