Since 1980, populations of wild boar (Sus scrofa) have increased over the species' entire European range. This increase has led to conflicts because wild boars cause crop damage amounting to several million U.S. dollars every year. Wildlife management agencies promote and financially support 3 major methods to reduce the loss: (1) intensive harvest, (2) supplemental feeding in forests to bait animals for easier shooting and to distract them from agricultural fields, and (3) building electrical fences around crops at risk. Our objective was to investigate how effective these methods were in reducing field damage by wild boars. Based on data from 44 hunting territories in the Canton Thurgau, Switzerland, we related damage frequency to harvest success, supplemental feeding, and fencing effort by means of 2 multiple regression analyses. The analysis of mean damage frequency among territories (averaged over 3 years) and changes in damage frequency within territories from 1994 to 1996 showed that only hunting reduced damage by wild boars. Because our results question the effectiveness of wild boar management practices and wild boar populations and damage are increasing throughout Europe, we suggest that control efforts and funds be reconsidered. Because only hunting seems to clearly reduce wild boar damage, we suggest more emphasis be put on the development and introduction of new harvest models among local hunting teams.

During the last two decades, populations of the wild boar Sus scrofa in Europe have increased considerably and the species has spread into new areas over the entire continent. Because of the animals' impact on agriculture, livestock and biodiversity, and the resulting necessity of realistic management practices, we were interested in the key environmental factors responsible for this remarkable development. The study was based on data from the canton Thurgau, a region in north-eastern Switzerland. We used data on damage and hunting success to calculate a population density index and related it to eight variables describing ecological conditions, demography and hunting pressure (measured by the number of hunters) over a 25-year period. The analysis shows that the population increase correlates with higher than average winter and spring temperatures and improved food supply through more mast years and an increase in the area of maize cultivation. While favourable temperature conditions mainly reduce juvenile mortality, enhanced food availability is likely to boost reproductive success through younger age at first reproduction, larger litter size and earlier onset of oestrus within a season. Given this link between food and reproduction, supplemental feeding, a management practice recommended and very common all over Europe, should be reconsidered.

Positive correlations between male vocalization and reproductive success have been documented for many animal species. They are usually based on differences between males in vocalization rate, duration or repertoire size. Here, we present probably the first field study linking differences in territorial overlap and mating status to differences in a single, clearly definable song element, the 'Snarr'. Male water pipits, Anthus spinoletta, with high Snarr scores were mated more often than males with low scores, and their territories overlapped less with those of neighbours. Although correlating positively with male body condition, the frequency of the Snarr did not reflect male age, territory size, territory quality in terms of food and paternal performance. Therefore, it seems unlikely that the higher mating success of males with high Snarr scores results from active female choice of high-quality males; rather, high Snarr scores seem to signal dominance in males. Likely mechanisms that produce the link between vocalization and mating success, and potential costs that prevent some males from producing the Snarr at a higher rate, are discussed. Copyright 1998 The Association for the Study of Animal Behaviour. Copyright 1998 The Association for the Study of Animal Behaviour.