We compiled and analyzed data from 1987 to 2004 on feral pig (Sus scrofa) population indices affected by control methods at Hakalau Forest National Wildlife Refuge, a tropical montane rainforest on the island of Hawai`i. These population data included annual sign surveys, the number of pigs removed from fenced management units, and age and reproductive status from necropsies. There was an even sex ratio (1 female:1.02 males) within the population and within age classes. Boars lived to 60 months while sows lived to 48 months. Pregnancy occurred throughout the annual cycle, but lactation peaked in April?June. Reproductive rates also increased with age, peaking at 2?4 years in sows. We reconstructed the standing population within a 2,024-ha closed unit to examine demographic processes. We estimated that annual removal of >41?43% of the population was necessary to affect a decline. Annual sign surveys showed a strong and sustained decline in pig activity after 1997 relative to unmanaged areas. When compared with staff or public hunting, snaring was the most efficient control method.
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