Mike Allison, Founder & CEO of Jelen Premier Wildlife Services, delves into the importance of habitat manipulation as a management aid for the purposes of species management, and promotion of biodiversity.
In humans, there are some fundamental but quite specific requirements that dictate where we are likely to live. In most cases our decision to live somewhere will be influenced by a few basic factors. Generally, our choice of residence will be:
a) Secure, providing some privacy and freedom from disturbance.
b) Warm and dry, able to protect us from the worst of the weather, and
c) Not too far from the shops, although obviously we have the means and the inclination to travel some distance to find food!
If where we live isn’t secure or we’re constantly disturbed, or if it is cold and damp or draughty, and is miles away from where we can buy food, then it is unlikely that we will stay there, and certainly not a place we’d like to bring up our children. When we consider this, then human nature isn’t too far removed from that of wild deer.
The basic requirements a deer will need in order be happy to live somewhere are:
a) Security - in the form of sufficient cover where it is difficult for predators (including man) to sneak up and do them harm, and where they can ruminate peacefully until the next feeding bout.
b) Shelter - An area that provides adequate protection from the elements. Protection from the worst of the weather (wind and rain) that can literally sap the energy from an animal.
c) Feeding - A source of nutritional food capable of providing the necessary energy requirements to keep the animal warm and ensure adequate growth.
In areas where these are provided, then deer will happily live there for some time until an event causes the loss of one of the elements.
If there is temporary disruption to any of those elements, then deer may continue to live there for a short time after the event, but ultimately the function of the elements will need to be restored relatively quickly or the deer will simply move away – an influence in population dynamics.
Security
Deer naturally seek security from potential danger throughout most of their lives. As a prey species, they are equipped with an ‘early warning system’ in the form of a set of acute senses (scent, sight and hearing) that will normally alert them of impending danger.
However, without cover – offering some form of physical protection mechanism – deer would never relax sufficiently to allow their physiological well-being to be maintained.
Such cover is generally ‘policed’ by other species such as Jays, Magpies, Blackbirds and Woodpigeons – all of which can act as primary alarms to the presence of intruders.
Through evolution, wild deer have come to understand what the sounds and physical behaviour of woodland animals means. How many times have experienced ‘stalkers had stalks ruined through the clatter of early-morning woodpigeons as they are disturbed.
Deer have long since learned that such an occurrence spells ‘danger’ and usually make for cover long before we have ever been aware of their presence. Similarly we have learned – through experience – that stalking in woodland where such a commotion has been initiated through our mere presence is in most cases a waste of time.
Without good cover and security, wild deer will always be at risk from predators and those who otherwise seek to harm them.
Shelter
The provision of shelter from the elements helps ensure that most of the nutritional value in what the deer eats is utilised in the most efficient ways – primarily to be converted into a useable protein resource to promote bone and muscle development, and secondarily as a source of energy to keep warm.
Where deer are subjected to adverse weather conditions with little in the way of adequate shelter, then energy demands to merely keep warm can easily outstrip the supply of energy provided from the food they eat.
In cases of prolonged extreme weather conditions such as persistent wind and rain, or deep snow cover, then shortfalls in energy demands on the animal are met by utilising stored fat reserves – built up in times of plenty.
Therein lies the beginning of a ‘vicious circle’. Depleted fat reserves reduce the animal’s ability to keep itself warm. If it can’t keep warm, then the energy demands are even higher, and result in weight loss.
A hungry animal becomes lethargic, and an inefficient feeder – consequently it is placed at greater risk from predators.
In herding species such as Red, Fallow and Sika, ‘poor-doers’ are generally forced out of the herd by stronger herd members as their defensive instinct ‘mechanism’ comes into play. This increases stress in the affected animal/s, and inevitable premature death occurs.
Feeding
Without an adequate source of nutritional feed all animals will fail to thrive. Most of the movement patterns of deer are equally influenced by the amount of feed available to them, the nutritional quality and the type of feed. However, the feeding patterns will differ between the species.
The smaller species (e.g. Roe & Muntjac) are termed as ‘Concentrate Selectors’ and the larger species (e.g. Red & Fallow) are termed as ‘Bulk Feeders/Grazers‘. Sika tend to be intermediate feeders and have adaptations of both concentrate selectors and grass/roughage eaters.
In relation to their body size the reticulorumen of Concentrate Selectors is smaller. These deer select the leaves and buds of plant species that are: a) easily digestible, and b) are of high nutritional value. Although due to their highly selective dietary requirements, the peaks of feeding activity will be more regular than the grazers.
For example these deer will show a preference for legumes (Lucerne, Clovers etc.) over grasses and more fibrous plant material which are more difficult to digest.
The Bulk Feeders/Grazers, whilst able to adequately process legumes, show a preference for fresh grasses and fibrous plant material.
These animals have a much longer overall intestinal tract, but with a shorter proportion of large intestine to small intestine compared to Concentrate Selectors.
This is indicative of a more protracted digestive process of fibrous plant material compared to the relatively swift digestive process of the Concentrate Selectors.
It is also interesting to note that the intestinal tract of Sika is somewhat longer than that of the larger Red deer. This suggests that Sika are more suited to feeding on highly fibrous, less digestible plant material, similar to the diet of goats.
This probably goes some way to explain why Sika are able to survive in thick conifer woodlands on a less than favourable diet compared to the Concentrate Selectors and the true Grazers.
Whatever their dietary preferences, when deer locate a reliable and preferable feed source, close to where adequate shelter and security is provided, then this provides a suitable habitat, and the chances are that they will live there.
As man essentially controls the food source, effectively managing the habitat and diet, then man also has the capability to improve the diet through manipulation of the habitat.
Habitat Manipulation
The ability to influence deer movement patterns through manipulation of the their habitat must not be underestimated. If their movement and feeding patterns can be manipulated through careful habitat management, then so can their impact on forestry and agricultural crops in the area.
However, in order for us to achieve adequate forestry and tree protection, habitat manipulation would need to be part of a co-operative management strategy that takes into account not only local cropping systems, but also deer manager/stalker ability.
Habitat manipulation can be affected in several ways, including:
1) Deer Glades - The development of deer glades using seed mixtures containing species that deer find more attractive than the crops that we are trying to protect. The species of plants to be established will be dependent on the species of deer that present in the area, and therefore are likely to use it – or those that we want to use it!
To prevent planted deer glades from being over-grazed, then some form of rotational controls can be implemented through the use of temporary fencing.
In addition, rotational controls can also highlight usage impact, although it is unlikely that such areas will provide reliable indications of overall deer density. The reason being that the planting of preferred plant species will undoubtedly attract a greater concentration of deer.
It must be remembered, that in most cases, the aim is not to attract deer to an area, but to provide alternative vegetation and browse in the proximity of commercial crops to prevent damage to commercial interests or ESA’s.
2) Scrub Areas - By promoting scrub areas and thick cover where deer can not only feel ‘safe’, but also be provided with adequate shelter from the weather, then we can expect them to remain in the area, provided they are left relatively free from disturbance.
3) Strategic Mowing/Swiping - We can use these methods to effectively simulate controlled grazing to a point. Naturally open areas, or artificially created open areas (such as power cable wayleaves) can be used to great effect in this way.
The aim of strategic mowing is to create a mosaic of differing plant growth stages. For example the effect of random mowing through power cable wayleaves not only stimulates the growth of new, succulent and highly palatable vegetation, but also creates ’pathways’ where deer will naturally travel. The fact that the 'pathways’ are bordered by taller mature plant vegetation gives deer a sense of security.
These can be used as effective deer control areas, but it is important that shooting takes place only from high seats. On-foot stalking in such areas will only serve to ‘educate’ animals as to the dangers of visiting them, and consequently disrupt the deer’s diurnal rhythms. In such cases, the use of these as control areas is rendered ineffective.
In our efforts to effectively control and manage deer populations, there can be no substitute for sound, reliable field-based knowledge and experience.
The above should be seen as another facet of deer management as part of part of the wider strategic management process, rather than a stand-alone method of deer management & control.
Mike Allison Founder & CEO Jelen Premier Wildlife Services.
Jelen Premier Wildife Services is a UK leader in Conservation Grade Deer Control, Training, Consultancy and Live Animal Capture since 1998. Find out more here:premierwildlife
Also, If you'd like to take up deer stalking a great place to start is by taking the Proficient Deer Stalker Certificate Level 1. You can find out more about the course here: deer-stalking-course
