Individual study: A review of the efficacy of supplementary winter feeding of red deer Cervus elaphus in Europe and North America
Putman R.J. & Staines B.W. (2004) Supplementary winter feeding of wild red deer Cervus elaphus in Europe and North America: Justifications, feeding practice and effectiveness. Mammal Review, 34, 285-306
Supplementary feeding of deer in winter is a widespread practice in parts of northern Europe and North America. Such feeding is undertaken for a variety of reasons, including maintenance of high densities of animals for hunting, improving fecundity, increasing over-winter survival and as a management tool aimed at reducing damage to crops, forestry plantations and natural habitats. The efficacy of such feeding programmes is however, often unclear.
Evidence for the effects of winter feeding of wild red deer Cervus elaphus on body weight, antler weight of stags, fecundity, over-winter survival and a reduction in environmental damage was reviewed, drawing together relevant information from over 60 publications.
Weight, fecundity & survival: Overall, it was found that winter feeding of wild/free-ranging red deer had little beneficial effect on increasing body weight or fecundity. The effect on antler weight (size and quality) was highly variable and probably due to mineral availability (primarily calcium) in the habitats in which deer lived, and not food provision. More surprisingly, there was also variability in the effects of feeding upon survival, with no clear picture emerging. The can perhaps in part be explained in that it was evident that to be effective, food supplementation is required early in the winter and not just when animals are already in poor condition and heavy mortalities are occurring.
Habitat damage: Empirical evidence for a reduction in environmental damage, particularly to commercial forestry plantations and semi-natural/natural woodlands, was again inconclusive. Some studies showed a decrease in damage, some no effect, and others a significant increase, there was no clear pattern.
Associated problems: A number of problems associated with winter-feeding became apparent. Some individuals coming regularly to feeding stations relied on this food to such an extent that foraging on natural food declined to almost nothing. If the feed was less than the daily required intake, these individuals regularly lost weight. Observations also showed that feeding at stations was very uneven, with dominant stags monopolising the food supply over females and younger animals, until they had had their fill.
Supplemental feeding in the UK: In a survey of deer managers in Scotland, 58 (88%) of 66 respondents offering winter feed considered that it was effective in achieving their various objectives. The remaining eight either gave no opinion or were uncertain as to whether their declared objectives had really been met. However, in terms of cost-effectiveness, only 43 (65%) considered winter-feeding was cost-effective, four thought that it was definitely not and 19 were uncertain.
On the balance of the available evidence, with some exceptions, it seems that supplementary feeding is of little benefit to red deer in the UK, but any cessation of supplementary feeding should be undertaken gradually.
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