strains can still be traced to the early releases, but South Australia's population, along with all others, is now largely recent farm escapees. This is having adverse effects on the integrity of wild herds, as now more and larger herds are being grown due to the superior genetics that have been attained by selective breeding. Wild red deer are a feral pest species in Australia, do considerable harm to the natural environment, and are a significant road traffic hazard. Argentina and Chile In Argentina and Chile, the red deer has had a potentially adverse impact on native animal species, such as the South Andean deer or huemul; the International Union for Conservation of Nature and Natural Resources has labelled the animal as one of the world's 100 worst invaders. Migration Red deer in Europe generally spend their winters at lower altitudes in more wooded terrain. During the summer, they migrate to higher elevations where food supplies are greater and better for the calving season. Taxonomy and evolution Until recently, biologists considered the red deer and elk or wapiti (C. canadensis) the same species, forming a continuous distribution throughout temperate Eurasia and North America. This belief was based largely on the fully fertile hybrids that can be produced under captive conditions. Genetic evidence clearly shows the wapiti and red deer form two separate species. Another member of the red deer group which may represent a separate species is C. corsicanus. If so, C. corsicanus includes the subspecies C. e. barbarus (perhaps a synonym of C. e. corsicanus), and is restricted to Maghreb in North Africa, Corsica, and Sardinia. The International Union for Conservation of Nature originally listed nine subspecies of red deer (Cervus elaphus): three as endangered, one as vulnerable, one as near threatened, and four without enough data to give a category (Data Deficient). The species as a whole, however, is listed as least concern. However, this was based on the traditional classification of red deer as one species (Cervus elaphus), including the wapiti. The common red deer is also known as simply red deer. Selected members of the red deer species group are listed in the table below. Of the ones listed, C. e. hippelaphus and C. e. scoticus may be junior synonyms. Cervus elaphus appeared in Europe by the beginning of the Middle Pleistocene around 800,000 years ago. These earliest forms belonged to the palaeosubspecies Cervus elaphus acoronatus.