up to 1966:
Ornithology in Bonn, Museum Alexander Koenig
1967 to 1979:
Biomineralization
Bonn, University, Institut für Zytologie
Bochum, University, Lehrstuhl für Zellmorphologie
since 1990:
studies on population biology and socio biology of the barn owl (Tyto alba) by banding
since 1997:
foundation and management of a group of barn owl ringers (TytoHelgoland) in northern Germany. The data are stored electronically and will be made accessible to all members of the group.