Food of the Red-Backed Shrike Lanius collurio: A Comparison of Three Methods of Diet Analysis
2003
Tryjanowski, Piotr | Karg, Małgorzata K. | Karg, Jerzy
Diet of the Red-backed Shrike was analysed from collars in nestlings, pellets and prey remains in larders. All the material was collected from the same territories in Western Poland. A total of 2855 prey items were identified from all samples. Insects, mainly Coleoptera, Hymenoptera and Orthoptera constituted 98.9% of all prey items identified. To determine diet and predict impact of food sources on Red-backed Shrike populations, three methods should be used together (pellet content analyses, collar sampling and analysing larders). Our findings suggest that pellet content analyses is an easy and non-invasive method for estimating prey diversity and frequency index. Collars are necessary to determine nestling diets. Analyses of prey remains in larders should be used to find large prey, handled before eating. In more advanced geographical analysis of the content of shrike diet, we suggested to pool together data obtained by different methods from the same place, and/or carefully assign methods of diet analyses.
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