In the present era of climatic change and extreme pollution, we are all looking for a ‘green’ solution.
Wind energy is emerging as the perfect green solution to meet our energy needs. It is becoming popular in many cities like Texas as it drastically lowers your electricity costs while dramatically cutting down on carbon-dioxide emissions.
But like everything, it also has its downsides, especially to wildlife and their habitats. Its turbine blades are notorious for killing a significant population of birds. But do windmills kill birds in reality? Let’s find out!
Do windmills kill birds?
Yes, windmills do indeed kill birds and bats. Despite being the cleanest energy source, it is responsible for causing significant unnatural death of birds and bats.
Ways in which Windmills cause deaths in birds:
The first is by direct collision. Even though it gives a perception of moving slowly, the wind turbine blades move at an extremely high speed. The speed at its outer tip can be as high as 179 mph or 288 km per hour. It is sufficient to slice off the wings of even large birds like eagles, vultures, falcons, hawks, etc.
Often these predator birds have their eyes set on the ground in search of their prey, and thus, they miss the windmills, leading to the casualty.
Another reason for the casualty is the design of the windmills. The old and traditional designs of the windmills have a lattice that attracts the birds as an ideal perching space. Perching there becomes a death trap for them.
The second reason for the bird’s death is barotrauma- a disease triggered by the windmills. Because of the rapidly moving wind turbines, the air pressure of the nearby air drops significantly. When birds like bats fly too close to the windmills, this sudden exposure to low pressure damages the body tissues, especially that of the lungs.
This causes internal injuries, which almost every time leads to the death of the birds.
Apart from the above, the location of the windmills can also be held responsible for the bird’s death. Many a time, they are located on the path of the migratory birds, thereby making them easy targets.
How many birds are killed by wind turbines?
Even though birds and bats die from several other causes, wind turbines lead the show.
While accurate counting is not possible due to several factors like the impossibility to locate every dead bird under turbines, many dead birds eaten by scavengers, etc. Still, it is estimated that the rotating turbine blades kill tens and thousands of birds every year.
Several studies suggest that in a wind farm, the average bird death count can be around 140,000 to 500,000 annually.
The biggest threat for large, high-conservation value and threatened birds like the bald eagles, golden eagles, Swainson’s hawks, red-tails, burrowing owls, white-tailed kites, etc. Many of these birds have a low reproductive rate that triggers the danger of these birds becoming extinct.
Windmills are also responsible for the mass mortality of bats. Bats play a crucial role in our ecosystem. They feed on hordes of various pest insects. They also pollinate flowers and disperse seeds that help in regenerating rainforests. They, too, have a low reproductive rate which makes them vulnerable to becoming endangered species.
Is there a solution?
Thankfully, the scene is not as dismal as its looks. Today, plenty of mitigation measures are taken to reduce bird fatalities due to this renewable energy source. A few of them are:
- Before installing a wind turbine in any area, any wind energy company must complete the environmental impact assessments (EIA’s). It ensures minimal damage as it also covers information to critical questions like an estimate of how many birds are killed by windmills in that area, impacts on other wildlife, etc.
- Another effective mitigation measure has been to till the soil surrounding the base of the wind turbines. It makes the area unattractive to kestrels. A research study revealed the step reducing the death due to collisions by about 75 to 100 percent in two years span.
- Another highly effective and simple measure has been to paint one of the blades of the wind turbines black. It helped reduce the birds’ fatality rate drastically. According to the scientific theory, the move helps the birds to better perceive the windmills as a threat and take evasive action.
- Another effective measure has been to use a bat deterrent system which creates an ultrasonic acoustic field of the same range as bats’ natural echolocation frequencies, using speakers. It disturbs the ability of the bats to receive and interpret their own echolocation calls and forces them to evacuate the area. The method has reduced the bat’s fatalities by 54 percent.
- Another popular method has been the use of 3D- printed echolocation whistles which help divert the bat’s path.
- Illuminating turbines with ultraviolet light is another method that shows promising results though their efficacy is yet to be proved.
- The turbine designs have been improved such that they become less attractive to birds as a perching space.
Related Read: Evolution Of Birds | How Have Birds Evolved Over Time?
While it is not possible to reduce the death of birds to zero due to the windmills, several measures have made it possible today to reduce the number of fatalities drastically. Several promising developments have given the wind industry plenty of hope to become a clean source and not as ‘bird choppers.’