HABITAT AND SURVIVAL OF CAPERCAILLIE TETRAO-UROGALLUS NESTS AND BROODS IN THE BAVARIAN ALPS

The capercaillie Tetrao urogallus has become endangered in central Europe, most probably as a result of habitat changes. Breeding ecology was studied by following radio-tagged hens through egg-laying, incubation, and chick-rearing between 1988 and 1992. Loss of chicks rather than nests was the main determinant of reproductive success. All adult hens incubated, two-thirds of the nests hatched, and one-fifth of the chicks survived until autumn. Both nests and broods were mostly found in habitats with rich ground vegetation. Nest cover was probably a major factor for hatching success. Brood home ranges averaged 148 ha during the period from hatching to late summer. Broods preferred old forest stands with rich ground vegetation and high invertebrate abundance, which occur under moderate canopy cover. Bilberry Vaccinium myrtillus was an essential feature for brood habitat at forest stand, home range, and landscape scale, and should therefore be a major goal for capercaillie habitat management in central Europe.