Albrycht, M.*, Merta, D., Bobek, J. and Ulejczyk, S. 2016. The Demographic Pattern of Wild Boars (Sus scrofa) Inhabiting Fragmented Forest in North-Eastern Poland. Baltic Forestry 22(2): 251-258.

   The high density of wild boar populations in the farmland-forest landscape on north-eastern Poland has resulted in crop damage and conflict with farmers. Any effective harvest plan has to consider the population demography. Therefore, the objective of the study was to estimate the age-sex structure and reproduction in the population of wild boars inhabiting an area of 1,310 km2, where the share of fragmented forest amounted to 26.8 %. The study material consisted of 234 wild boars harvested during drive hunting between October and mid-January from 2012 to 2014. Among the animals harvested there were 63.3 % piglets, 15.8 % of yearlings and 20.9 % older individuals. The differences in carcass mass (CM) and in kidney fat index (KFI) between piglets and yearlings and between yearlings and adults were statistically significant, both of males and females. The sex ratio was male-biased in piglets (1:0.78) but in the cumulated group of yearlings and adult females predominated (1:1.53). In 117 studied females, the percentage share of pregnant individuals was 39.3 % and the mean size of litter was 5.2 ± 0.29. All pregnant female piglets were aged 9-12 months and had significantly higher CM (37.6 ± 2.30 kg vs. 29.6 ± 1.82 kg) and KFI (1.67 ± 0.06 vs. 1.35 ± 0.05) than not pregnant ones. The farrowing took place in all months of the year except October. More than half of the piglets (57.4 %) were born in March, April and May. The harvest strategy to reduce the population density of wild boar in the study area is discussed.

Keywords: pregnancy, fat reserves, litter size, age structure, sex ratio, carcass mass.