Wolves are carnivores and specialised in hunting hoofed game (cloven-hoofed animals). As a matter of fact, the wolf is at the top of its habitat's food pyramid. The number of wolves in an area is naturally and solely determined by the food resources available and any diseases but is not regulated by a predator. Similarly, the wolves naturally regulate the number of wild ungulates whose counterpart they are.
Wolves in central Europe feed primarily on roe deer, red deer and wild boar, locally also on fallow deer and mouflons. Elks and reindeer are often the wolves' primary prey in Scandinavia. Wolves hunt and kill the animals which they can access and defeat most easily. Apart from old, sick and weak animals, these are mainly young animals. As far as large game animals such as wild boar and red deer that are able to defend themselves is concerned, it is to be expected that wolves will mainly hunt young animals. This does not mean that wolves would not attack any healthy, strong and alert animals if they have an opportunity to do so. However, their success rate for hunting these animals will be much lower than that for weakened and inexperienced animals.
Since wolves mainly kill prey of an age or in a state in which they do not reproduce (too young, too old, too weak), they release the mature and reproducing prey animals from food and space competition. This improves the condition of the reproducing animals which in turn leads to a higher number of offspring or to stronger offspring. Furthermore, the selection of sick prey animals impairs the spread of infectious diseases. According to this theory, the prey animals' vitality improves under the influence of natural predators.
The interrelations between wolves and their wild-living prey animals are very complex and dynamic as many factors are involved. Various studies show that an increase in the predator population need not necessarily affect the prey population. There are known cases where the number of prey animals remained stable in a certain area although the wolf population increased there but also studies which documented a significant reduction in the prey population caused by wolves.
Even though the wolf may reduce the number of hoofed game animals, it will not eradicate its natural prey. Exceptions are wild species that humans settled artificially in habitats different to their own natural ones or that originate from regions where wolves have never been resident. In the event of danger, mouflons, for example, retreat to steep, inaccessible cliffs in their natural habitat. They do not have such a possibility of retreat in the lowland and are thus easy prey for wolves. Therefore, it cannot be ruled out that local wild mouflon populations which have been settled here in Germany by humans will be eradicated again by wolves.
Strategies of game to avoid enemies
Our local hoofed game animals and their predators such as the wolf, lynx and bear have developed together in the same habitats over millions of years and adapted to each other. Hoofed game has numerous strategies to avoid its predators. After all it is not defenceless and without a chance when it faces a wolf even after the wolf's absence for one or two centuries. The game animals have not "forgotten" the strategies to avoid this enemy which they developed over a long period of time but are definitely able to readapt themselves to these natural four-legged hunters.
Whether at all and to what extent the game animals can apply their inherited strategies vis-à-vis large returning predators is, last but not least, also determined by the way of hunting and the hunting pressure of human hunters. Potentially successful behaviour for avoiding the human (high-seat) hunter, such as going to open spaces only under cover of darkness, is ineffective when it comes to wolves; wolves hunt at night as well as in bright daylight. Thickets are no obstacle for them. They can use their noses to get the scent of their prey and surprising it there is even more likely than in open areas. What all predator – prey systems have in common is that the prey animals use the existing habitat in such a way that the energetic cost – benefit ratio between feeding and avoidance of the enemy is best.
Under natural conditions, e.g. without hunting with modern firearms, red deer, which originate from steppes, would also go to large open areas offering good grazing possibilities during the day where these animals, as creatures with good vision, can see natural enemies from afar and escape by giving them a wide berth. It is high-seat hunting which is carried out over several months a year that turns the diurnal red deer into nocturnal forest animals. Wild boar probably first and foremost rely on their ability to defend themselves. Therefore, wolves apparently mainly hunt boar piglets in Upper Lusatia. Roe deer, however, can neither rely on their size or strength nor on extensive escape strategies to oppose wolves. One adaptation strategy of this small, solitary-living hoofed game species is probably to appear in different places at different times. This makes it more difficult for the wolf to look for the animals and the "two-legged" hunter will have to wait in the raised hide for a much longer time.
Assuming that a pack of four to ten wolves is hunting on an average area of 25,000 hectares (ha) (250 km²), there is a wolf density of 0.02 to 0.04 animals per 100 ha in Lusatia. By comparison: on average there is one human hunter per every 100 ha of hunting area in Germany. It can thus be assumed that the hoofed game will mainly continue to focus its enemy avoidance behaviour on the human hunters. Of course, it will also try to adapt to the grey hunter under these conditions. Enemy avoidance strategies used by the game animals against two-legged and four-legged hunters need not necessarily be opposed to each other. The formation of large red deer herds is known in areas where wolves are resident as well as in areas without wolves. The formation of so-called large herds is often a local, temporary phenomenon which is mainly connected to the food offer. Open grazing areas, such as grassland, rapeseed and grain growing areas, offer large amounts of attractive food so that many animals gather there. At the same time, it can be assumed that red deer feel safer in a larger group because many eyes see more and it is more difficult for enemies to select a specific animal from a large group, reducing the risk for each single animal. This applies to both wolves, as the four-legged hunters, and humans, as the two-legged hunters. Large red deer herds are a natural phenomenon irrespective of whether there are wolves in the area or not.
Hoofed game research in Upper Lusatia
Within the scope of a red deer telemetry study conducted by the TU Dresden (Nitze 2012) in Upper Lusatia, 14 adult red deer animals were fitted and marked with VHF and GPS-GSM neck-collar transmitters to examine the wolf's possible impact on the behaviour of its prey. The main study area was located in the eastern part of the Upper Lusatia military training area and the open areas adjacent to the south. This area is part of the home range of a reproducing wolf pack ("Daubitz pack"). Thanks to the connection of telemetry, visual monitoring (including camera-trap monitoring) and the mapping of prey animals killed, this study provided information on the habitat use pattern and behaviour of this game species in a wolf area in Germany for the first time. It showed that the red deer's gender-specific, seasonal, habitat use patterns that exist in areas without wolves also apply to this wolf territory with a similar area coverage. The annual home ranges (365-day period) of male game animals had an average size of approx. 1,300 ha (Kernel95cw) and approx. 470 ha (Kernel95cw) for female animals. The red deer's home range did not shift much over the years. Nor did the habitat use patterns vary much in terms of time. A clear, seasonal differentiation between summer, rutting and winter home ranges was verifiable generally only for the stags. This marked seasonality that is typical of this species is the reason why the annual home ranges of male red deer are much larger. None of the marked animals migrated from the known home range in the wolf country to other regions in Upper Lusatia for shorter or longer periods of time.
Only correspondingly long-term periods of monitoring, which have not so far been carried out, will be able to provide findings about any long-term effects. The second project stage of the telemetry study ended in December 2015.
Please refer to the website of the Forest Zoology Department of TU Dresden for more information on this research project.