Our Tolerance for Bird Deaths at Energy Facilities

Significant Losses at Power Plants 

and Transmission Lines

Bird Populations Slumping:

Since the release of bird status reports at the Asilomar Conference, bird populations have continued to slump, and the list of North American birds with declining populations or otherwise at risk at the regional and continental levels has increased since 2002 where 131 species were then designated (USFWS 2002). 

Today, these include 147 species on the 2008 Birds of Conservation Concern list (USFWS 2008), 92 birds federally listed as Threatened or Endangered on the Endangered Species Act (ESA), State-listed species, and species listed as high priorities on the U.S. Shorebird Conservation Plan, among others. 

The growing documented and suspected impacts of structures on birds—from direct collision mortality, barotrauma, electrocutions, cumulative effects, and from habitat fragmentation, disturbance and site avoidance—bode poorly for our bird populations.

Migratory birds—of which there are currently 836 designated species—are a Federal trust resource managed and protected by the U.S. Fish and Wildlife Service (USFWS). The published list of the 836 species is found at 50 CFR Ch. 1, 10.13, List of Migratory Birds.*

Reasons for Bird Deaths:

The estimated cumulative impact of collisions with wind turbines is several orders of magnitude lower than the estimated impacts from the leading anthropogenic causes of bird mortality.

The available data estimates the following causes of death (in millions per year) for birds:

• Aircraft .08
• Wind turbines .58 to.573
• Large communication towers 6.8
• Power plants 14.33
• Cellular, radio & microwave towers 4 to 50
• Cars and trucks 50 to 100
• Agriculture 67
• Pesticides 72
• Building windows 97 to 976
• Hunting 100
• Transmission lines 175
• Domestic and feral cats 210 to 3,700

Thus, the biggest threat to birds are cats that live some part of the day outside where they hunt and kill birds.  They kill up to 3.7 billion birds per year.

This data also reveals our tolerance for bird deaths associated with energy-related projects, including power plants, and transmission lines.  Deaths at either of these types of facilities far exceed deaths at wind farms.

Bird Deaths and Wind Farms:

Still, we may want to answer the questions:  

• How many more cumulative bird deaths do we want to tolerate at wind farms projects?
• Are wind farms especially dangerous to specific species of birds that we have a heightened need to protect, like eagles?
• Can wind farm operators design wind farms to mitigate bird deaths?
• Can they monitor and operate wind farms to mitigate bird deaths?

I will answer these questions in future posts in this series. 

* This discussion is derived from sources I researched in connection with the Environmental Dispute Resolution course I teach.  I am not including citations to those sources, and I acknowledge that some of this discussion is directly lifted from those sources (with my apologies to the authors I failed to credit).  Eventually, I plan to write a law review article on this topic and the original sources will receive credit there.