A flamingo cleans its feathers. (Photo: Martin Meissner, AP)
The Trust for Endangered Wildlife’s drone unit made history last week by installing specialized warning lights on an active municipal power line near Sedgefield in the Western Cape.
This initiative aims to drastically reduce the risk of fatal collisions with power lines for the local flamingo population on the Garden Route.
The overhead warning lights, commonly known as OWL devices (Overhead Warning Lights), are a type of driver equipped with flashing LED lights. These devices are strategically placed on the power line next to the N2 bridge that spans the Swartvlei lagoon. This makes the lines visible to birds flying at night, which is an important safety measure for the many water birds and birds of prey in the area.
The Swartvlei lagoon is not only a certified Ramsar wetland, but also an integral part of the Garden Route biosphere. This area is located in the Cape Floristic Region. Among the endangered species that call this wetland system home is the rare tawny owl (Tyto capensis) as well as the Greater Flamingo (Phoenicopterus roseus) and the Lesser Flamingo (Phoeniconaias minor).
Local bird watchers have long expressed concern about the impact the power lines have on the flamingos, especially since these birds often fly over the bridge at night. The BirdLife SA Lakes Bird Club approached the Endangered Wildlife Trust for help with mitigation measures after the danger to the birds became increasingly clear.
The overhead warning lights, commonly known as OWL devices (Overhead Warning Lights), are a type of driver equipped with flashing LED lights. (Photo: Provided)
The trust has been working with Eskom for more than 30 years to reduce the impact of energy infrastructure on wildlife, and has already marked thousands of kilometers of power lines nationwide to prevent collisions by birds such as vultures and eagles.
According to Tim Carr, owner of Reflections Eco-Reserve and member of the Lakes bird club, the process of getting permission was a crucial step. He explains that the club approached the trust when they realized that permission from the Knysna Municipality was needed for the installation of the devices.
“The club’s members, together with BirdLife Plettenberg Bay, raised more than R100 000 to cover the cost of the installation. This is a phenomenal example of cooperation in conservation. Reflections Eco-Reserve and the Lakes Bird Club are proud to be part of this success. We are extremely grateful to all parties involved,” says Carr.
What makes this project truly remarkable is the manner in which the installation was carried out. The Endangered Wildlife Trust’s drone unit has been subcontracted to install the OWL devices on the section of the line that spans the lagoon.
The installation was done on an active power line without interrupting the electricity supply to the local communities – a technical achievement that is considered a world first.
Lourens Leeuwner, the Trust for Endangered Wildlife’s head of operations and manager of the drone unit, emphasizes the importance of the cooperation between various agencies.
“If it wasn’t for the Knysna municipality agreeing to this installation, it wouldn’t have been possible and we wouldn’t have been able to play such a key role in ensuring that flamingos no longer fly into the power lines.
“Collaboration was key in this operation. The Knysna Municipality, Sedgefield’s fire brigade and provincial traffic officers were all on hand to ensure that our crews, working along the N2, were safe.
“The Garden Route National Park also gave permission for us to use drones over the area and SANParks staff were on site themselves,” says Leeuwner.
He emphasized that these devices will also protect other waterfowl and birds of prey in the area from possible deaths due to collisions.
The decision to use exactly OWL devices is based on thorough scientific research. In 2016, the Trust for Endangered Wildlife 12 already equipped twelve Lesser Flamingos with GPS devices for a research project from Eskom. More recently, in 2024 and 2025, another 11 Greater Flamingos and three Lesser Flamingos were tagged in collaboration with the Mpumalanga Department of Agriculture and Rural Development.
Data from these projects showed that flamingo species undertake significant movements between different water bodies in the region and that the majority of these flights take place at night. Tests in various locations around the country have shown that the OWL devices, with their flashing LED lights, are extremely effective in improving the visibility of power lines and thus preventing collisions in the dark.