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DONKERS H (2018) Year-round diet of the Tawny Owl Strix aluco in woodland on poor soils in West-Brabant. LIMOSA 91 (2): 46-60.

From January 2012 through December 2017, pellets of Tawny Owls were collected on a regular basis at night roosts below hunting posts in de Rucphense Bossen and Visdonk (Southwestern Netherlands). The Rucphense Bossen is a 830 ha conifer plantation, mainly covered by Scots Pine. Here a total of 8677 prey items were collected and identified. Another 2664 prey items were collected at Visdonk, a nearby area of fragmented woodland (110 ha), bordered by farmland (Fig. 1).
Woodmice Apodemus sylvaticus (54.3%, based on biomass) dominated in the diet in both areas, in all years and all seasons (Fig. 2) followed by Bank Voles Myodes glareolus (14.4%), birds (11.7%), Rabbits Oryctolagus cuniculus (4.3%), Field Voles Microtus agrestis (4%), Frogs Rana sp. (3.4%) and Whitetoothed Shrews (Crocidura russula) (2.8%). All other species were represented by less than 2%.
After mammals, invertebrates were the most numerous prey group. Within this group, Minotaur Beetles Typhaeus typhoeus (60.1%) were most frequently found, followed by Cockchafers Melolontha melolontha (20.2%).
Contrary to most of the studies that were conducted in mixed or deciduous woods, small rodents were the most abundantly represented prey in the pellets in all seasons. This may be due to the lack of thick groundcover in the study area which makes it easy to localize and catch small rodents, even in spring and summer.
In general, old deciduous woodland is considered to be optimal habitat for Tawny Owls. In the poor coniferous study area the density of territories however was high (3/100 ha) and the dominance of a few species throughout seasons and years might indicate a rich food condition. Unfortunately information about reproduction is lacking.

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limosa 91.2 2018
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