Mighty Ducks: How do wind turbines affect ducks?

Guest Blog | January 26, 2015 | Energy Policy, Wind

As duck hunting season comes to a close, flocks of hunters have enjoyed a potentially record-breaking season thanks in part to good weather and successful conservation efforts. Despite strong conservation measures which aided this year’s hunt, ducks do face a number of threats that must be recognized and mitigated. As more wind turbines are installed throughout the country, researchers, communities and hunters are asking: how do wind turbines affect ducks?

Duck hunting is not only a cultural heritage, it also supports hundreds of millions of dollars in economic activity every year. The Fish and Wildlife Service conducts an annual review of waterfowl hunter activity. For the most recent review, FWS estimates that some 881,400 duck hunters spent nearly 6.2 million days hunting afield. Estimated expenditures by duck hunters runs over $600 million annually. In 2013, FWS estimates hunters bagged 13.7 million ducks.

Despite the seemingly high levels of duck hunting, duck populations seem to be quite stable. Ducks Unlimited, the world’s leader in wetlands and waterfowl conservation, announced in its 2014 Waterfowl Forecast that the number of breeding ducks was estimated at 49.2 million birds. The 2014 forecast was 8% higher than the year before, and the largest number since standardized surveys began in 1955, according to DU. Coincidentally, wind turbine capacity also grew by 8% last year, and wind power has become a substantial energy source over the past decade.

Before wading into a discussion about wind turbines and ducks, it is important to evaluate current science on the topic. Most of the available data show wind turbines have a minimal impact on birds, and some research specific to ducks does exist. One paper shows that some ducks may reduce usage of wetlands near wind farms. This “avoidance” behavior may be a double-edged sword: avoiding areas with wind turbines may reduce habitat usage, but could also prevent interaction with a wind turbine that could lead to mortality. (Not to ruffle any feathers, but ducks also exhibit extreme avoidance to hunters in powerboats and hunters in general. Those interactions can also lead to mortality.) That same paper suggests that as ducks become more comfortable with wind turbines over time, they may habituate to the turbines and exhibit less avoidance behavior.

This image shows the actual flight path of ducks and geese that were recorded flying near an offshore wind farm in Denmark. The black lines show that the birds generally fly around the wind farm altogether. Less than 1% flew close enough to a turbine (the red dots) to present any threat of collision. (Desholm and Kahlert, 2005)

But avoidance alone does not provide a full picture of the complexity of duck interactions with wind turbines. Another study evaluates duck flight patterns to estimate collision risks. Based on this research, ducks generally see wind turbines well in advance and rarely venture into a wind farm. However, even if waterfowl venture into a wind farm, there’s no guarantee of a collision. Flight altitude, or height, also plays a role in collision risk. Wind turbine blades pose the biggest collision risk to birds. If ducks fly below the lowest blade tip height, or above the highest blade tip height, the overall risk of collision is relatively minor. Citing another study, the paper states, “In total, less than 1 % of the tracked birds passed close enough to the turbine to be at any risk of collision.”

Even though wind turbines can have an effect on ducks, the effect need not be all negative. Wind farm development can include conservation easements to protect high priority duck habitat. Protecting high quality habitat can be a better protector of ducks than banning wind farms. If it seems counterintuitive that wind energy can protect ducks, consider this: hunters are among the greatest forces for duck conservation. Hunters get their ducks in a row by supporting conservation through the purchase of federal duck stamps, joining conservation organizations and respecting bag limits – and fewer hunters could imperil duck conservation. If hunters can help ducks, it is not daffy to believe that wind turbines can as well.

In reality, hunting is a small portion of duck mortality. Some experts suggest hunting, with 13.7 million birds taken in 2013, only accounts for 7-8% of duck mortality.  Other causes of duck mortality include predators, starvation, disease and even foul weather. In comparison, wind turbines have been estimated to kill 214,000 and 368,000 birds annually. That’s birds, not ducks. Since hunting kills approximately 37 to 64 times as many ducks as wind turbines kill birds, it seems unlikely that wind turbines will have population-level impacts on ducks anytime soon. Never-the-less, wind farm developers would be wise to take steps that benefit ducks and their habitats. And they don’t need to wing it: maintaining a high level of communication with conservation organizations can further protect the cultural (and economic) benefits of duck hunting.

In addition to easements, wind energy can help preserve ducks in other ways. Wind energy emits no greenhouse gas emissions and, as such, can help reduce the impacts of climate change. As Ducks Unlimited puts it, “Climate models indicate that warming temperatures will cause shifts in precipitation patterns, more extreme weather events, and significant changes in land use. Ducks could be hit hard by these changes.” Fossil fuels and the pollution they generate are much more dangerous for ducks (and birds as a whole) than wind turbines. Ducks frequently die, en masse, at oil ponds. One recent event saw 1,600 ducks die in a single pond. Chronic pollution from fossil fuel power plants can negatively impact duck reproduction, especially through mercury-contaminated waterways. For a pollution-free, clean energy resource, wind energy fits the bill.

The fact remains that wind turbine installations have substantially increased while, at the same time, duck populations have reached record levels. Perhaps the relationship between the mighty duck and wind energy may just continue along swimmingly.


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