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Résumé :
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1. The feeding habits of five species of titmouse in an area in the English Midlands have been observed over a period of three years. 2. It is shown that each species of titmouse has a characteristic height distribution of foraging activities, and preferences for certain species of trees and parts of trees. The height distribution of some species varies from season to season, and may be modified by an unusual abundance or lack of some food. 3. It is shown that the height-frequency distribution of the foraging activities of each species, and also the favoured feeding tree, differ from those of the other four species. 4. From time to time the ecological separations between different species have been found to disappear. It has been possible to show that these extinctions of ecological separation have coincided with temporary superabundances of food. 5. The ecological implications of the differences in feeding habits are discussed.
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