RAPTOR acoustic fence as a solution to the wild boar problem in urban areas:

 

Wild boar populations have risen sharply across Europe and other continents in recent decades, for a variety of reasons. At the same time, their natural habitat is offering them less and less space.  

Wild boars have virtually no natural predators, apart from humans, and they are able to distinguish very clearly between ‘dangerous’ and ‘harmless’ humans:

They are hunted intensively in the woods and fields. Without this controlled hunting, populations would literally explode and the damage to agricultural land would be devastating.





However, these intelligent wild boars evade hunting pressure or, in their search for new food sources, venture into residential areas on the outskirts of towns and even into city centres.
Hunting is not permitted in residential areas, and from the wild boars’ perspective, people and even dogs are completely harmless. Some people even feed the wild boars, thereby encouraging a wild boar infestation!


The intense hunting pressure in the surrounding fields and woods is literally driving the wild boars into the city, which is much safer for them. 
As a result, they are increasingly losing their instinct to flee from humans and are venturing deep into residential areas. The food sources they find here are also very attractive: perfect meadows, compost heaps, windfall fruit, rubbish bins, etc.
In contrast to the woods and fields, where they are hunted intensively, there are almost no dangers in the city. The only exception might be urban hunters, although their options are usually very limited.
The material damage alone caused by wild boars in parks, gardens, cemeteries and sports grounds quickly amounts to five- to six-figure sums in euros per year per local authority.

 

Furthermore, in urban areas there is always a risk that animals will feel cornered and become aggressive. Aggressive wild boars can cause life-threatening injuries. That is why it is always advisable to adopt a very defensive stance when encountering them! However, this could lead the wild boars to perceive us humans as ‘harmless’ or inferior, causing them to lose their wariness even further – a vicious circle.

Car accidents involving wildlife are also on the rise with the increased presence of wild boars near urban areas.

 

Worst-case scenario: an unprotected town becomes more attractive to wild boars than the forest:

Figure 1: Unprotected town surrounded by woodland. The town is already more attractive than the woodland; a wild boar infestation is imminent. Red: area perceived as dangerous; green: attractive area

 

 

Counter-strategy:

Keep wild boars away from residential areas using the ‘RAPTOR’ acoustic fence:

 

To keep wild boars away from residential areas, these areas must be made significantly less attractive to wild boars and perceived as more dangerous than the surrounding countryside.

A method is required that constantly conveys a sense of danger to wild boars, yet is harmless to humans and compatible with urban life. The automated acoustic simulation of danger (RAPTOR principle) in the language of wild boars is a new approach with great potential. In combination with a systematic package of measures, even difficult cases can be brought under control:

 

The concept can be applied in a simplified form as a preventive measure in towns where the pressure is not yet high. However, it is also suitable for towns where massive damage has been occurring for years and the animals have already become accustomed to the area. In these cases, the effort required is significantly greater and a consistent approach must be taken.

The concept comprises three interlinked components that reinforce each other’s effectiveness:


 

A:      Acoustic fence with RAPTOR wild boar repeller

B:      ‘Conditioning’ supporting measures

C:      Communicating prohibited and permitted areas

Figure 2: An example town surrounded by forest. The acoustic fence using the RAPTOR wild boar repeller makes the town unattractive and perceived as dangerous. A wild boar infestation can be prevented.
Red, orange: simulated danger zone, green: safe zone: ‘permitted’ area
 

 ad  A:      acoustic fence with RAPTOR wild boar repeller

The RAPTOR wild boar repeller simulates dangerous situations acoustically using the language of wild boars. This device has proven its effectiveness in agriculture for years in keeping wild boars at distance. If these devices are installed at a distance of 200–400 metres from one another in a buffer zone around the town or at critical points, this creates an ‘acoustic fence’ which wild boars avoid.
To ensure that the wild boar sounds are barely audible within the residential area itself, we use highly directional loudspeakers in combination with simple yet effective noise barriers.

 
This acoustic fence switches on automatically at night and acts as a significant barrier to wild boars. Other animals are less affected. The system can be adjusted so that the sound is (almost) inaudible within the town. Noise limits, e.g. 50dB, can be met.

The inhabited area becomes unattractive to wild boars because it can no longer be reached without passing through this ‘dangerous’ buffer zone. Any existing wild boar infestation would dissipate, or indeed never arise in the first place.
As experience with the RAPTOR wild boar repellent in agriculture shows, wild boars generally keep a safe distance from the RAPTOR devices.



Image: RAPTOR R31 wild boar deterrent with a simple yet effective noise barrier to ward off wild boar infestations.

 ad  B:      “conditioning” accompanying measures

Whilst in straightforward cases the acoustic RAPTOR fence will suffice for deterrence, in more challenging situations accompanying measures are necessary and recommended during the first few weeks.
This is particularly true if the animals have been comfortable in inhabited areas for a long time, know their feeding and sleeping spots well, and have not yet experienced any real danger.

These accompanying measures may include, for example, deterrence methods such as driving the animals away with beaters and dogs, or deterrence by the town gamekeeper, etc.
If such measures are carried out in isolation, the animals may return once they realise the danger has passed.


However, when combined with RAPTOR wild boar deterrent devices placed around the town, the wild boars will perceive a constant threat. Through the combination of experiencing real danger and a constant simulated threat, they are much more likely to avoid these areas.

It works even better if the accompanying measures are ‘carried out in a conditioned manner’.
In other words, the simulated threat posed by the RAPTOR is directly linked to the real threat posed by the accompanying measure. (e.g. manual deterrence and the activation of the RAPTOR devices take place on the same day)
The animals then perceive the sounds of the RAPTOR as a much greater and constant real danger. Returning to their old roosts or feeding grounds would then be perceived as far too dangerous.

If the wild boars have long been familiar with their feeding grounds in the town, or already have daytime roosts in the buffer zone or in a residential area, the accompanying measures must be implemented all the more consistently in order to achieve a change in behaviour.
If the animals have up to this moment not experienced any danger in this area, they will try to find loopholes. Consistent accompanying measures in the first few weeks after installation of the RAPTOR wild boar repeller fence can prevent this.

The nature and intensity of possible accompanying measures and how they are carried out in a ‘conditioning’ manner depend on the individual case. We would be happy to advise you further on this.
 

ad   C:      Communicating prohibited / permitted areas

Wild boars are very intelligent, and this can be used to teach the animals which areas are ‘off-limits’. This method, when combined with the RAPTOR acoustic fence, has great long-term potential and works best if it is implemented consistently.

Procedure:
Define the urban area plus a suitable buffer zone (e.g. 300m) as a ‘forbidden/dangerous area’. The inhabited area becomes unattractive to wild boars if it can no longer be reached without passing through this ‘dangerous’ buffer zone.



Within this buffer zone, danger is communicated on several levels:
RAPTOR acoustic fence, see (A)
night-time accompanying measures, if necessary
driving operations out of this area, if necessary; daytime access to this buffer zone must not be permitted
hunting measures where possible (e.g. by the town gamekeeper)

Within the urban area itself, any food sources should be difficult or impossible to reach; a ban on feeding is essential.

 

A clearly visible boundary between the ‘restricted/dangerous area’ and the ‘permitted area’ would be beneficial. These boundaries could, for example, be marked by:

- paths, roads, or forest/field or forest/meadow crossings

By, for example, carrying out occasional night-time patrols right along this boundary, the animals would be made aware of the boundary.

 

However, the animals also need alternative areas – ‘permitted areas’ – where they face less danger.

If there is sufficient food available here, there is no reason to take the risk of crossing the RAPTOR acoustic fence. Should the ‘permitted areas’ offer too little food, temporary diversionary feeding can be used to divert the animals away from their old feeding grounds in the town. In the long term, the ‘permitted areas’ can be moved further and further away.

 

The practical feasibility of the permitted/prohibited area method is also highly situation-dependent, as is the implementation of suitable accompanying measures. We would be happy to advise further on this.

 

Empirical data on this concept is currently being compiled; however, there is a long history of positive experience with the RAPTOR wild boar repellent in agriculture, as well as with noise protection using directed sound and noise barriers. Studies confirm the effectiveness of the RAPTOR wild boar repellent