POPULATION CONTRACTION OF THE WHITE-BACKED WOODPECKER DENDROCOPOS-LEUCOTOS IN FINLAND AS A CONSEQUENCE OF HABITAT ALTERATION

The population decline of the white-backed woodpecker Dendrocopos leuc otos in Finland is presented and factors affecting this decrease are a nalysed The woodpecker favours mature, deciduous forests which include many dead trees. These forests have been clearcut and thinned heavily from the 1950s. Winter bird counts from the late 1950s to the 1980s s how declines of over 90%. The size of the present population is estima ted at 30-50 breeding pairs. Fledging success and adult survival rate are not exceptionally low compared to the results of other studies but juvenile mortality appears to be very high as the recruitment rate is low. The breeding population is also very sparse: the mean distance b etween nearest nests was 15 km. In order to preserve the white-backed woodpecker from extinction in Finland a network of deciduous forests f avoured by the woodpecker has been proposed.