The expansion of highways and roads can fragment natural habitats and thus decrease the viability of ungulate subpopulations. It can also increase the number of vehicle collisions with wildlife. Although collisions apparently contribute to only a minor part of the annual mortality for most ungulate populations, they have become a serious road‐safety problem in Europe, the United States, and Japan. To better understand this threat to biodiversity and road safety, we reviewed European and, secondarily, North‐American and Japanese literature on ungulate traffic collisions. In contrast to the results of some long‐term studies, we argue that the relationship suggested between the number of road kills and traffic volume is confounded by population dynamics, changes in traffic volume, and sampling intensity. Although sexes may run distinct seasonal risks of collision, the age and sex composition of road kills reflect population structure in the field. We also argue that observed seasonal and daily patterns in the number of road kills, related to life‐history features of the species involved, should form the template for solutions to the problem. We found no strong evidence of the effects of permanent warning signs, 90° light mirrors, scent, or acoustic fencing on the number of kills per crossing. To reduce the risk of ungulate traffic collisions, we recommend a combination of fencing and wildlife passages for roads and railroads that combine high traffic volume with high speed. For secondary roads we recommend seasonal application of intermittently lighted warning signs, triggered if possible by the ungulates. We emphasize the need for educational programs.

From 1987 to 1992 diet and condition of two populations of wild boar which received no supplementary feeding were studied in the Veluwe area, a large area of heathlands and forests in The Netherlands, and were compared with those obtained in a previous study (1974–1976), when supplementary food was provided. Composition of stomach contents depended mainly on season, mast availability, and area‐specific factors, whereas sex and age were of little or no importance. Density dependence was found for the decrease in mast (tree seed) consumption from autumn to winter. In autumn, and in winters of rich mast years, mast was the main constituent of the diet. In winters of poor mast years this was replaced by broadleaved grasses in one area and by broadleaved grasses, wavy hairgrass, and roots in the other. We found no important differences between the stomach contents of animals receiving no supplementation, and the natural fraction during a period of supplementary feeding. Variation in body weight was related mainly to age and sex, but also to mast availability. Judged by relative loss of body weight and decrease of bone marrow fat, juveniles seemed to suffer more from poor mast availability than adults. The decrease in body weight from autumn to winter was greater when population density was high. In poor mast years, recruitment into the population receiving no supplementation depended on the availability of broadleaved grasses; in rich years, recruitment was still lower than in populations receiving supplementary feeding. In populations receiving supplementary feeding, recruitment seemed independent of mast availability.

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