Population structure and reproductive ecology of wild pigs at the northern edge of the North American invasive range.

Wild pigs (Sus scrofa) have been expanding their range in Canada during recent decades. While high reproductive output is typically reported in wild pigs, reproductive performance at the northern edge of the North American invasive range is not well characterized. In this study, we describe the population structure and reproductive parameters of wild pigs in Alberta, Canada, estimate age of juvenile and sub-adults based on a Gompertz growth model fitted on wild pigs of known age from Texas, and test hypotheses regarding their reproductive ecology in this northern context. With a high proportion of reproductively active females (68%), and litter sizes comparable to other regions (median 5, IQR [4-8]), wild pigs in Alberta maintained a high reproductive potential. However, age estimates suggested low survival within the first year which may limit population growth in this region, potentially working in favor of on-going control program. Continued monitoring of wild pig population structure and reproductive parameters is essential to understanding population dynamics and planning control efforts in relation to changing environmental conditions.