Medium voltage overhead lines present a hazard to certain bird species whose body size or wing span is in the clearance range of such medium voltage overhead lines. Such bird species can bridge the clearance between a conductor and earthed parts or between two conductive parts with their body or wings or via a faeces stream when sitting down - as is their typical behaviour - at an elevated point such as a medium voltage overhead line. In Germany, the species most endangered by electric shock are storks, raptors and owls. Measures for the protection of birds are especially aimed at these species.

One of the most important milestones of bird protection on medium voltage overhead lines is the resumption of the protection of birds in DIN VDE 0210 (VDE 0210):1985 12 according to which cross members, insulator supports and other components of overhead transmission lines are to be designed in a way that birds are not offered a seating area in the vicinity of active conductors. This requirement was adopted without modification in the currently valid construction standard for overhead lines DIN EN 50423-3-4 (VDE 0210-12).

Another important step was the VDEW catalogue of measures for the protection of birds on overhead lines in the 1991 version. It included a description of essential measures for the implementation of bird protection on medium voltage overhead lines. This catalogue of measures was elaborated and signed by representatives of network operators, nature protection organisations and the Federal Ministry for the Environment, Nature Conservation and Reactor Safety. It is a specification of bird protection with respect to relevant overhead line standards.

For the first time, the protection of birds on medium voltage overhead lines was put on a legal footing in § 53 of the 2002 edition of the Federal Nature Conservation Act (Bundesnaturschutzgesetz - BNatSchG). The objective here is to protect bird species by constructing new masts and technical components of medium voltage overhead lines in a way that birds are protected against electric shock.

This VDE application guide applies for medium voltage overhead lines from AC 1 kV up to and including AC 45 kV. It applies for operators of electrical power systems. Annexes A and B of the VDE application guide temporarily include requirements for components for bird protection and their testing as a product standard on this subject does not yet exist.