Timing and distance of natal dispersal for wild boar Sus scrofa in Sweden

Abstract

In order to estimate age at natal dispersal and dispersal distance, wild boars Sus scrofa were studied in Sweden by use of mark-recapture and telemetry. To de scribe the average natal dispersal in the population, we applied a sigmoid re gression model to analyse the age specific distance to the natal site. We used the first and second order derivatives of the model to determine at which ave rage age dispersal begins, reaches its maximum rate and ceases. The average dispersal distance was estimated by the maximum value of the model. Using this method, we reached the conclusion that male wild boars begin to disperse at the age of 10 months, reach their maximum dispersal rate at the age of 13 months, and that dispersal ceases at the age of 16 months. At that age, they have dispersed 16.6 km from their natal sites. For females, the corresponding ages were 7 ,9 and 11 months, with a dispersal distance of 4.5 km. The results fol low the prevalent opinion on natal dispersal in polygynous mammals. Dispersal distances are generally short with a negative exponential probability distribu tion. Dispersal reaches its maximum rate during the age at which sexual matu rity is occurring, and males disperse longer distances than females.

Exposure of Wild Boar to Mycobacterium tuberculosis Complex in France since 2000 Is Consistent with the Distribution of Bovine Tuberculosis Outbreaks in Cattle

“…Our results show that exposure of wild boar to MTC is consistent with TB outbreaks in cattle, especially when interpreting optical density with the 0.5 threshold. Moreover, using this threshold, the mean (median, respectively) distance between a seropositive wild boar and the nearest cattle outbreak is 13 km (12 km) which is compatible with the daily movement capacities of a wild boar (from 1 to 16 km, [28]) or their dispersal distances (4.90+/−5.65 km for males, reaching 38km for some individuals, in [29]; 16.6 km for males, in [30]).…”

Long-Lasting, Kin-Directed Female Interactions in a Spatially Structured Wild Boar Social Network

“…Social bonds between related females have been demonstrated to have a positive effect on female fitness, including increased offspring survival, in other group-living species [65]–[68]. In contrast to females, wild boar males, particularly adults, tended to form associations with unrelated males which seems to conform with polygynous mating system and male-biased dispersal in this species [21], [22]. However, given the low number of adult males in this study and the potential bias in relatedness estimates [24], [25], this result should be treated with caution.…”

Survival of Wild Boars in a Variable Environment: Unexpected Life-history Variation in an Unusual Ungulate

“…The sensitivity of survival of juvenile males to environmental conditions and their low survival as yearlings might be linked to different dispersal patterns of the sexes. Male wild boars disperse further than females (Truvé and Lemel 2003), and the disruption of family links of male yearlings during the rut is considered final (Beuerle 1975).…”