Cameras and radars won’t save the eagles

Filed under: 'Green' Killing Machines vs Birds,Hot News,Studies |

DTBird only 7% effective when it works, says Norwegian study

Avian radar and video systems are targeting the wind farm market, claiming they are the solution to the turbines’ lethal impact on birds and bats. Save the Eagles International (STEI) and the World Council for Nature (WCFN) wish to alert to the fact that these perceived “solutions” are in fact counterproductive. They will, on the contrary, expand the mortality to important bird habitats and other sensitive areas previously spared by windfarm developers.

Download the evaluation report: Evaluation of the DTBird video-system at the Smøla wind-power plant

The DTBird video system, to name one, consists of a sound-warning device linked to four daylight video-cameras installed on the tower of each wind turbine, covering in principle all angles up to 150 meters away, and 50% to 300 meters (1). This system works only during daylight hours, so it is of no use for saving bats, migrating songbirds (which travel by night to avoid over-heating), and other useful creatures like owls.

Avian Radar System

Avian Radar System

Yet, wind turbines kill owls by the thousand – e.g. about 270 a year at the Altamont Pass wind farm in California (2). Regarding song birds, these are butchered by the million by the fast moving blade tips (3). As for bats, which are attracted to insects that swarm around wind turbines, the massacre is even greater (4). All this killing, by the way, will have serious consequences for agriculture, because bats and owls help control insects and rodents, respectively.

Thus, DTBird is useless for stopping 75-85% of the mortality caused by wind turbines. And as we shall see from a study made at Smola, Norway, it is only effective for scaring away 7% of the birds that approach wind turbines during the day.

Let’s do the maths: 7% of 15-25% = 1 – 1.75%. This means that DTBird, during the periods when all its cameras and related equipment are working perfectly, can reduce total mortality at wind farms by 1.75% at best.

DTbird includes a software said to be able to recognize birds from insects, falling leaves and other unwanted visual effects. It is also said to automatically trigger a dissuading sound when signals identified as birds are getting too close to the turbine. But if we read the evaluation made by NINA (Norwegian Institute for Nature Research), which tested the system during 6 months for two wind turbines on the island of Smola, it so happens that the warning mechanism is sometimes triggered by raindrops, insects and shifting clouds (5). NINA warns that these “false positives” could cause habituation, reducing the effectiveness of the dissuasion (6).

In any event, habituation or not, the performance of the DTBird video-system is dismal: “In only 7% of all video sequences where warning/dissuasion was iniciated, was a visible flight response observed” (7). In other words, when it works, DTBird is INEFFECTIVE at scaring away 93% of the birds that approach its wind turbine in the daytime.

If this weren’t enough, breakdowns are frequent. During the 6-month trial at the hands of NINA technicians, in spring and summer, the 8 DTBird cameras malfunctioned 3 times, and the detection module for one of the two turbines was out of order for a month (5). One can imagine how difficult it would be to maintain in excellent working order, say 10 modules and 40 video-cameras installed on 10 wind turbines, during 25 years (including winters).

Thus, even if the system were effective at 100% instead of 7% (or 1.75%), an army of state inspectors would be needed. They would have to check daily on the wind farm assigned to them, to ensure that each turbine effectively emits dissuading sounds when birds come close, and that the creatures actually react by avoiding the turbine. For we must remember that, in most countries, certain birds are so rare that the death of a single individual could have a significant impact on the conservation status of its population – e.g. the Bonelli’s Eagle in France .

This gives an idea of how enormous the task would be, to ensure that the cameras and detection modules may be relied upon every day of the year. So much so that it would be unrealistic to consider mitigation by electronic devices, whichever the system or its maker.

Avian radars, which are supposed to detect birds and stop wind turbines in time to avoid collisions, are an equally unrealistic “solution”. Actually, once the wind turbines are installed, and as governments can’t afford an army of uncorruptible “windspectors”, the radar unit is quite simply left unused. At the Kennedy Ranch wind farm in Texas, it was found that the avian radar had not stopped a single wind turbine in 18 months of operation. Actually, a witness watched in horror as a pelican got whacked out of the sky (8).

It’s a fact that has to do with human nature: windfarm owners won’t cut into their profits willingly. Indeed, stopping wind turbines abruptly several times a day wears the brakes and lowers production. It is also costly to maintain in excellent working order, 365 days a year, dozens of cameras – half of them facing the sky (and the rain) – and associated sensitive electronic equipment.

In a nutshell, video and radar systems may look good on paper, but they are impractical. In fact, their only use is to help developers obtain planning approvals for wind turbines in protected bird flyways and other sensitive habitats. They are thus counterproductive, helping destroy our most valued wildlife. Logically, they should be banned altogether from windfarm projects, as officials often base their favourable decisions on mere plans to install such mitigation systems, whether or not these will prove effective in the end.

Mark Duchamp
Chairman, World Council for Nature
President, Save the Eagles International


  1. NINA’s evaluation report: Evaluation of the DTBird video-system at the Smøla wind-power plant
  2. Wind turbines kill an average of 270 burrowing owls per year at the Altamont Pass windfarm in California: 270 burrowing owls
  4. How much wildlife can USA afford to kill/
  5. The truth about avian radars

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