Diet, ecology, and biosecurity: analysis of owl pellets from Skomer Island

Compton, Emily, Daley, Laura F., Stubbings, Ed M., Büche, Birgitte I. and Wood, Matthew J ORCID: 0000-0003-0920-8396 (2016) Diet, ecology, and biosecurity: analysis of owl pellets from Skomer Island. Birds in Wales, 13 (1). pp. 57-72.

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Owls regurgitate indigestible components of their diet as pellets, which can provide valuable information on predator feeding behaviour and prey populations. We examined the prey remains in the pellets of Little Owls Athene noctua and Short-Eared Owls Asio flammeus on Skomer Island in 2014, and compared our results to previous studies to investigate changes in owl diet from as early as 1970. The dominant prey groups were small mammals; particularly Skomer Voles Myodes glareolus skomerensis (35.7% of Little Owl diet in 2014; 36.7% of Short-Eared Owl diet) and birds (29.8% of Short-Eared Owl diet in 2014). Wood Mouse Apodemus sylvaticus, Common Shrew Sorex araneus, Pygmy Shrew Sorex minutus, and Common Frog Rana temporaria were also consumed by both owl species, and House Mouse Mus domesticus and European Rabbit Oryctolagus cuniculus by Short-Eared Owls. Pellet analysis may not be effective in detecting the predation of smaller prey items of owls, such as invertebrates. Most notably, we found that Short-Eared Owls travel to the mainland and Skokholm Island to hunt: species not found on Skomer were found in pellets, including House Mouse, European Mole Talpa europaea, Brown Rat Rattus norvegicus and even hair from European Badger Meles meles; none of which are present on Skomer Island. This presents a potential risk to island biosecurity from invasive small mammals: we recommend regular monitoring of owl pellet remains as an early-warning indicator of the potential introduction of invasive species, and an opportunity to study ecological dynamics of small mammal populations.

Item Type: Article
Article Type: Article
Subjects: Q Science > QL Zoology
Q Science > QL Zoology > QL605 Chordates. Vertebrates > QL671-699 Birds
Divisions: Schools and Research Institutes > School of Education and Science
Research Priority Areas: Place, Environment and Community
Depositing User: Matt Wood
Date Deposited: 03 Dec 2020 10:33
Last Modified: 31 Aug 2023 08:58

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