NEST-SITE PREFERENCE BY GREYLAG GEESE ANSER-ANSER IN REEDBEDS OF DIFFERENT HARVEST AGE

Maintenance of reedbeds and their associated avifauna requires interve ntion management to modify natural succession by means of, for example , reed cutting. Nest site density of Greylag Geese Anser anser in rela tion to time since reedbeds were last harvested was studied at Vejlern e nature reserve, Denmark (57 degrees 00-07'N, 8 degrees 50'-9 degrees 10'E). Low nest densities were found in areas in the first four years after cutting followed by high densities in areas unharvested for fiv e or six years. Subsequently, nest density remained high for four to s even years (depending on site) before declining to low levels again. A reas cut in the year of study and areas cut more than 16 years before contained virtually no nests. The increase in nest density with time s ince last harvest seemed to be related to an increase in vegetation co ver (reed stem density). Areas harvested more than 16 years before pro bably became too dense for the geese, and newly harvested areas had to o low a shoot density, hence their low nest density. However, move det ailed studies are needed to establish causal relationships.