Why Control Deer?
Adult deer have no predators that predate on them in the UK. New born deer can be taken by fox and in Scotland they can also be taken by Sea Eagles and Golden Eagles. These predators don’t seem to have a significant effect on the population. This means that if the deer population is left unchecked then numbers increase year on year. Wolves and bears predate on deer in Europe and will tend to select deer that will cost the least amount of effort and calories to catch. This will be the sick and infirm, and young and less experience with the occasional mature healthy animal. As deer managers we need to try and emulate this model and take out any old and sick first then a percentage of the young animals followed by a few mature animals each year. The idea is to have a spread of ages which will leave both experienced animals who know places of different foods at different times of the year and new animals gaining experience coming through. This will lead to less stress and turmoil within the population than would be if an unbalanced age class was left. There are variations on these factors from species to species.
What’s wrong with having a large population of deer?
Having an over population of deer in any particular area can have a negative impact on the deer themselves. As the population of deer reaches its carrying capacity on any particular piece of ground they will eat out all nutritious food plants. From then on they will be in competition with each other for an ever diminishing food source, which will mean turmoil within the population, stress and a loss of condition. When animals loose condition they become more vulnerable to parasites such as lice and worms and also diseases. With high populations there is more contact between animals and a greater risk of spreading disease and parasites. All these factors are multiplied in a hard winter. Controlling numbers of deer can give the population as a whole a much better chance of getting through the winter and although some may baulk at the thought of shooting deer, deer management carried out humanely and safely can save a lot of unnecessary suffering.
Other factors caused by an overpopulation of deer are a drop in biodiversity. The plants and shrubs that are eaten by deer are eaten out of the environment leaving a smaller diversity of plant species. Woodland that is holding a lot of fallow or reds is often bare at ground level up to a browse line. There is no regeneration of trees or plants because as soon as the new shoots come through they are cropped by the deer. There is no cover for ground nesting birds or little habitat for fauna; the wind can blow beneath the trees unchecked.
Road traffic accidents have increased in recent years with a rise in the deer population; this may also be due to an increase in public access to areas previously not open to the public leading to deer being pushed out of areas that were previously areas of daytime sanctuary for deer. Haldon Hill in Devon which has had a lot of woodland opened up to the public in recent years is an area that the DDM team has noticed an increase in deer casualties, with at least two animals seen struggling at the side of the road with broken backs this year. This is not to mention any human casualties that may have occurred that we do not have any information on.
The other factor that overpopulation has is crop damage. This can be crops eaten on farmland mostly caused by reds and fallow, tree damage mostly to newly planted trees by all deer species and damage to garden plants and shrubs. Surprisingly it is damage suffered by gardeners, land owners and foresters that can raise the most passion about deer, some that have suffered a lot of damage both materially and financially want every deer exterminated.
What is a population that is in balance with the environment?
Every piece of ground is different depending on its geography, climate, water table, soil, fertility, use and flora and fauna present. Depending on the balance of the above factors 100 acres of one piece of ground may be environmentally balanced with a much higher amount of deer than 100 acres of a barren piece of land. A deer manager needs to get to know a piece of ground, make visual sightings of deer on the ground to get an idea of species, numbers, sex ratio, age class etc. Then observe plant tree species present, how heavily browsed, slots, tracks and dung.
One person’s or organisation’s idea of a balanced population can be different to another person’s idea of a balanced population. For example if the protection of a tree crop is the landowner’s main concern then the deer population needs to be kept at a low density. Another landowner may have a nature trail with trees planted on it. Flora and fauna are the important factor and a certain amount of tree damage would be tolerated with the benefit of a higher deer population as long as it was not so high that it started to decrease biodiversity.
Devon Deer Management gathers information on the above factors and uses this information to create cull plans for each piece of ground. We believe that good deer management leads to a healthy population of deer that is balanced with the environment.