Variation in ranging and activity behaviour of European wild boar Sus scrofa in Sweden

Abstract

The present wild boar Sus scrofa population in Sweden mainly originates from animals that have escaped from enclosures. At some locations wild boars have evidently been released deliberately. Whatever their origin, rapid increases in both number and distribution of free-ranging wild boars have occurred. As wild boars are considered exotic in the Swedish fauna, sportsmen very often provide supplemental food in varying degrees, partly to facilitate and secure hunting possibilities, partly to keep wild boars out of farmed crops. In this paper we describe wild boar activity behaviour and intend to show how wild boar adjust their activity behaviour under different ambient conditions. The aim of our study was to increase the knowledge of managers to improve hunting effectivity and risk assessment concerning crop damage. The wild boars were, al most without exceptions, active during night. The mean time for an activity bout was 7.2 hours and the wild boars in the study area were only to a minor de gree adjusting their activity bout to the prevailing night length. However, the hour of sunset seemed to be the cue which triggered the onset of activity bouts. The mean distance that the wild boars travelled during activity bouts was 7.2 km and the estimated mean activity range was 104.4 ha. The mean effort when roaming the activity range was 110.9 m/ha. A substantial variance was typical for all activity variables. For activity distance, 72% of the variation was explained by adding wind speed, season, minimum temperature and snow cov er to our model. Significant effects of minimum temperature, snow cover and an interaction between activity time and minimum temperature explained 42% of the variation in activity range. The variation in relative air humidity explained 41% of the time active during an activity bout.

An assessment of the applicability of dung count to estimate the wild boar population density in a forest environment

“…This is mainly due to their intensive reproduction, hidden way of life (Fernández-Llario 2004), nocturnal activity (Lemel et al 2003), migration over longer distances and different feeding behaviour. In wild boar there is no sexual dimorphism, which, in other ungulates, can be used to correct the results of the counting.…”

“…Our results correspond with previously published data. For example, Gerard et al (1991), Lemel et al (2003) or Keuling et al (2008) reported that during daylight wild boars usually seek shelter and rest in young dense stands. According to Fonseca (2008), during the winter in southeastern Poland, wild boar stayed mainly in beech-hornbeam stands where they had the opportunity to feed on the beech-mast crop.…”

Genetic structure of the wild boar population in Portugal: Evidence of a recent bottleneck

“…It is described as a philopatric species depending on age class (Spitz and Janeau 1990;Lemel et al 2003), and presenting differences on annual and seasonal space use (Keuling et al 2007). However, evidence indicates low genetic flow among local populations (Okumura et al 1996).…”

The Wild Pig (Sus scrofa) Behavior – A Retrospective Study

“…Factors that affect food availability, like harsh winter and drought making the soil hard, were especially important and animals moved away from these areas at such times. During cold days they choose their resting places on sun exposed slopes that were readily available in the study area and during hot dry days they were observed to seek the cool moist forests with an abundance of wallows as reported by Singer et al [19] and Lemel et al [20]. Moisture was very important as the ground is easier to root and scents are better picked up and wild pigs were much more active under moist conditions.…”

“…Populations of wild pigs have also been seen to be primarily nocturnal, lying up during the day in dense cover. Spitz [22], Lemel et al [20], Pei [23] even noted that wild boar use sunset as an apparent cue for arousal which was very evident in this study as most of the sightings were noted after sunset. It was also observed that pigs moved greater distances away from both water sources and cover during the night.…”