PINE MARTEN HOME RANGES, NUMBERS AND PREDATION ON VERTEBRATES IN A DECIDUOUS FOREST (BIALOWIEZA NATIONAL-PARK, POLAND)

Pine marten Martes martes - prey relationships were studied in 1985/86 -1992/93 in Bialowieza National Park (E Poland), which protects the la st remnants of the pristine deciduous forests of European lowland. Win ter densities of martens, surveyed by snowtracking (in 1985/86-1988/89 and 1990/91), were from 4.44 to 6.49 inds/10 km(2). In 1991-93, six m artens were radiotracked. Their winter densities were 7.57 inds/10 km( 2) in 1991/92 and 3.6 inds/10 km(2) in 1992/93. Mean home range of mal e martens was 2.23 km(2) and that of females 1.49 km(2). Martens' rang es were smaller (by 33% on average) in autumn-winter than in spring-su mmer. Forest rodents, the bank vole Clethrionomys glareolus and the ye llow-necked mouse Apodemus flavicollis, were the main prey of martens. Autumn densities of these rodents were moderate in 1985-89 and 1992 ( 26-78 inds/ha), extremely high in 1990 (315 inds/ha, as an effect of h eavy crop of tree seeds in 1989), and very low in 1991 (11 inds/ha). N umbers of marten correlated with those of rodents with 1-year time lag . Every year, during 197 days of autumn-winter (1 October-15 April), m artens removed from 2 to 8 rodents from an average hectare (mean 5.5), which constituted from 2% to 31% (mean 15%) of autumn densities of ro dents. Predation impact was heavy in years of low densities of rodents and rather small during rodent outbreak. Martens' predation on 4 alte rnative prey in the cold seasons was estimated. During autumn-winter, they removed 0.01-0.18 birds, 0.1-2.0 shrews, and 0.2-3.7 frogs, and c onsumed 1.4-68.7 g of ungulate carcasses from 1 ha. Martens took the l argest quantities of alternative prey during the rodent crash