High-tech for animal welfare - DLR wildlife rescuers save 6000 fawns from death by mowing in Austria
Microwaves will complement the infrared system in future
Oberpfaffenhofen - Farmers and hunters in Austria who use the deer rescuer developed at the German Aerospace Centre (DLR) in Oberpfaffenhofen are reporting encouraging figures. Since 1999, they have been keeping statistics that show how many fawns are saved during spring mowing thanks to the devices. The number of animals brought to safety has increased significantly from year to year. This year alone, the number was around 2,500. To date, more than 6,000 fawns have been saved from death by mowing in Austria alone.
Roe deer leave their fawns well camouflaged in the tall grass during the first week of their lives. It is precisely at this time that farmers carry out their spring mowing. When a tractor approaches a fawn, it does not run away - it presses itself completely motionless to the ground. The consequences are fatal: in the old German states alone, it is estimated that around 60,000 fawns are killed each year during spring mowing. A total of 420,000 wild animals (hares, ground-nesting birds) are killed or mutilated.
Scientist Dr. Volker Tank from the DLR Institute of Remote Sensing Technology has been fighting against these figures since the late 1980s. When he obtained the hunting license required for falconry, he also learned about the thousands of fawns that die in the meadows shortly after birth. Tank patented the game rescuer in 1987. The company ISA-Industrieelektronik GmbH in Weiden took up the idea via the DLR technology transfer - the first prototype went into operation in 1998. The device works according to a relatively simple principle: a maximum of 16 infrared sensors are attached to an extendable support rod. They receive the body heat emitted by the fawn in the tall, cool grass. As soon as an animal is located, the wildlife rescuer sounds the alarm.
In practice, however, the system still has problems. As soon as the sun's rays fall on the meadow, the ground heats up unevenly, warm spots are detected and lead to annoying false alarms. The search for fawns, which often takes several hours, must therefore begin in the early hours of the morning. Although a strip six meters wide is searched in one pass with the Wildretter, the time required is still high.
In collaboration with the company ISA and the Technical University of Munich (Department of High Frequency Technology), DLR is therefore currently developing the second generation of the Wildlife Rescuer, which is not disturbed by sunshine and can also be attached to agricultural machinery. The device will make the search for wild animals much easier, as mowing can already be carried out during the search. In addition to the infrared sensors, microwave sensors will also be used to detect water - a fawn, like a human being, consists of 80 to 90 percent water. Infrared and microwave together detect "warm water", which is a clear indication of an animal in tall grass.
In addition to animal welfare, the Wild Rescuer also offers farmers protection against a major danger. If parts of killed animals are ensiled with the mown crop, Clostridium botulinum bacteria can develop in the silage, which produce a very strong toxin. If the silage is fed to cows, the cattle die from it.
Another area of application for the second-generation wildlife savior could be organic farming. No pesticides are used on the fields of "organic farmers". The weeds have to be chopped out of the soil using agricultural equipment. To prevent the crop plants from being destroyed in the process, they are sown at greater distances from each other from the outset. Because these spaced areas heat up quickly when exposed to sunlight, they are very popular with ground nesting birds, which build their nests there. In organic farming, many nests are destroyed and young birds killed year after year when weeding.
