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Résumé :
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The analysis of 1109 pellets collected between 1992 and 1994 in 2 localities of Northern Algeria: El-Harrach near Algiers (n= 615 pellets) and Boukhalfa near Tizi Ouzou (n = 494), brings some preliminary information on the diet of the north African sub-species of Tawny Owl (Strix aluco mauritanica). The breakdown of the 3694 identified prey is as follows: 3150 vertebrates (85.3%) and 544 invertebrates (14.7%). Among the vertebrates, mammals formed 43.6 % of the prey, birds 29.3 %, amphibians 15.2 % and reptiles 11.8 %. Insects are often captured but are of little importance in terms of biomass; they are dominated by Orthoptera (44.1 %) and Coleoptera (35.7 %). The Tawny Owl's diet is different in the 2 sites. At El-Harrach, a sub-urban area, the diet includes a large proportion of birds and synanthropic mammals (mice, rats) and a large number of a reptile Tarentola mauritanica. At Boukhalfa, a cultivated country area, mammals are more widely represented with a greater diversity ofspecies, and rodents form the main prey. We can notice an important proportion of amphibians in both areas. Preliminary results are given on seasonal variation at Boukhalfa and a comparison is done with the diet composition of the Barn Owl Tyto alba at El-Harrach. Mice represent the owls' basic prey in all the countries south of the Mediterranean sea. The originality of the Algerian analysis lies in the predominance of Mus musculus in comparison with Mus spretus.
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