Harvesting Eagles Part 2

On May 6 2016 the FWS and Interior Department announced a plan that would set massive industry bag limits for an eagle population that does not exist in the lower 48 states. In the case of the golden eagle, most of this eagle harvest will come from eagles that nest outside the US.

Since 1997 when the FWS repository first disclosed wind turbines as a major cause of death to eagles, wind energy has increased its deadly footprint by more than 10 times into golden eagle habitats located in the Western US. The Draft Programmatic Environmental Impact Statement created for the Eagle Rule Revision completely avoided the many thousands of eagle carcasses and autopsy records that exist from their repository eagles.  Even so, the limited and filtered data provided by the FWS does inadvertently give us a glimpse at the mortality impacts to eagles taking place from wind turbines.

What the FWS DPEIS is not telling America                                                                            

During the 1990's, a seven year study in the Altamont Pass region was conducted on radio-tagged golden eagles.                                                                                                 

"We recorded the deaths of 100 radio-tagged eagles during the seven-year study. Wind turbine blades killed at least 42, the actual number being higher because the blades occasionally destroyed the transmitter. Adding 12 electrocutions, all outside the WRA, at least 54 percent of all fatalities were attributed to electrical generation or transmission."

                                                                                                                                                       Not only did these turbines kill at least 42 golden eagles, this was a documented mortality rate more than 3 1/2 times greater than from electrocution. The DPEIS even states that wind turbines are a major cause of golden eagle deaths. This statement is given on page 99 and again with more details on page 195.    

                                                                                                                                                "Overall collisions from all sources (vehicle, line strikes, and turbine blade strikes) are estimated to kill about 500 golden eagles a year."                  

                                                                                                                                                 Looking at the latest FWS report  it can be seen the FWS relied heavily upon eagle mortality information from "a data set of unbiased cause-of mortality information for a sample of 386 satellite-tagged golden eagles from 1997–2013 to estimate the effect of current levels of anthropogenic mortality on those survival rates."                

From the 97 reported deaths to these satellite-tagged eagles it was reported that 11 or 11.3% (see Table) of these eagles died by electrocution.  Another 7 or 7.2%  died by collision. From the Altamont Hunt study it was determined that wind turbines were killing eagles at rate at least 3 1/2 times greater than from electrocution and turbines were killing at a rate 5.25 times higher than other sources of collision (Wire strikes, vehicle strikes).

The FWS data shows an 11.3% eagle fatality rate from electrocution. By multiplying it by 350%, we can reasonably assume that a very substantial or 38.5 percent of golden eagle mortality is coming from wind turbines.   We also get a similar turbine mortality rate by taking the FWS collision data (Wire strikes, vehicle strikes) showing 7 eagles fatalities. When multiplying by 525% we can again reasonably assume that a very substantial or 36.75 percent of golden eagle mortality is coming from wind turbines.

With these projected wind turbine mortality rates to eagles, the FWS may have just explained the cause of death to approximately 12,000-13,000 of the 33,000 bald and golden eagle carcasses received by the repository since 1997.