ZOEST JGA VAN & FUCHS P (1988) Hunting behaviour and prey supply by a breeding pair of the Little Owl Athene noctua. LIMOSA 61 (3): 105-112.

Little Owl Athene noctua Hunting behaviour and prey supply of a Little Owl breeding pair were studied in a peak year of voles Microtus arvalis in the Betuwe (central Netherlands) in an area where the typical habitat of the species was still intact. Direct field observations on hunting behaviour were combined with the monitoring of the prey supply using video equipment. During the nestling period the hunting efforts of the male were concentrated in a restricted area of c. 1.5 ha, using more or less fixed hunting routes (fig. I). The time spent on perches was variable and seemed related to perch height. Prey choice, determined by nestling demand, may determine the type of perch used by Little Owls. Prey was supplied mainly at night, only some prey being brought to the nestlings at daytime (fig. 2, 3). Weather conditions had a serious impact on prey supply. Male and female had about equal shares as far as numbers of prey items were concerned. In numbers, prey supply consisted mainly of invertebrates (90%); in weight, vertebrates were more important (59%) (tab. I). Usually series of similar prey types were supplied. Approximately one week before the young hatched, the numbers of prey (mainly consisting of vertebrates) supplied by the male to the female increased sharply (fig. 4). After hatching of the young the male continued to bring vertebrates, though in somewhat smaller numbers. Besides vertebrates the male mainly fed earthworms. The female started feeding the chicks 3-4 days after hatching. She concentrated on small invertebrate prey, e.g. insects (fig. 5). During the breeding season the shares of different prey types varied considerably (fig. 6). This variation appeared to be correlated with ambient temperature. The results suggest that the Little Owl needs a varied vertebrate and invertebrate fauna, which is present only in a heterogeneous landscape. This in turn depends strongly on agricultural management. However, further investigations are needed to formulate more accurately the Little Owl's habitat requirements.

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