Foraging Behavior of a Vertebrate Omnivore (Rattus Rattus): Meal Structure, Sampling, and Diet Breadth

摘要: Diet selection by the omnivorous black rat (Rattus rattus) was examined detailed analysis of stomach contents individuals from seven wild populations in Galapagos Islands. High within-meal diversity foods found: nearly all stomachs contained at least four foods, and many eight or more. Although 77% rats had eaten one potentially filling food, no individual (N = 173) only food its stomach. Meals tended to be dominated food; these dominant included a variety plant animal materials, but were rarely leaves. Nearly present trace amount (< 1% contents) (x 2.72 items per stomach; N 165). The prevalence traces large (leaves, stems, most fruits) suggests strong sampling component rats' foraging behavior. A high degree stereotypy found. Many individuals. In several cases same combination 2-4 selected 82-100% population sample. Two measures diet breadth (the number species cumulative members population) signif- icantly negatively correlated with density. abundance indices signifi- cantly positively These results are used evaluate current theoretical models nonspecialist