Aufzuchtshabitate für Auerhühner : ein Experiment mit Haushuhnküken

Capercaillie (Tetrao urogallus) populations in Switzerland declined seriously in the past decades. The national capercaillie action plan defines actions to improve forest structure and composition in order to further the populations of the largest grouse species. These habitat measures should focus on improving summer habitat for hens with chicks, because winter habitats are available in good quality and quantity. However, our knowledge on reproduction habitats in alpine conditions is limited. In this study, we investigated microclimatic conditions, i.e. plant wetness, and movement ability of barn fowl chicks in seven characteristic field layer types in the northern Swiss Lower Alps. In the experiment on movement ability, we worked with barn fowl instead of capercaillie chicks for methodological reasons. In the bilberry-dominated vegetation, we measured a significantly lower quantity of water than in the vegetation types without bilberry. In the movement experiment, we found no significant differences between the vegetation types. As a qualitative result, we observed that the chicks moved easily even in high (> 30 cm) and close bilberry vegetation. Our results suggest that bilberry-dominated vegetation provides better conditions for grouse chicks than wet meadows and pastures, because less water adheres to the bilberry plants. Thus, the chicks get less wet in bilberry vegetation, which probably has a positive influence on the survival of the chicks. Even tall and dense vegetation seems not to impede the movement of the chicks. The results of our experiment may not be directly transferable to the demands of capercaillie chicks. Nevertheless, our study provides further evidence for the importance of bilberry as capercaillie chick habitat, especially in regions with high precipitations