For more than a decade, wind developers have been notified by the U.S. Fish and Wildlife Service (FWS) that their wind projects may kill birds and, therefore, violate the Migratory Bird Treaty Act (MBTA).
However, research conducted at a sampling of more than 140 communication towers owned and operated by the Michigan Public Safety Communication System (MPSCS) shows that several state and federal agencies – including the FWS and U.S. Forest Service – are violating the MBTA on a regular basis.
Funded by the Michigan Attorney General's office and the Michigan State Police, Curry & Kerlinger conducted research over a three-year period. The results show that more than 11,000 birds, mostly night-migrating songbirds, were killed annually at 143 communication towers owned and operated by the MPSCS during the spring and fall migration seasons between 2003 and 2005.
The MPSCS towers, both with and without guy wires, are 380 feet to 485 feet tall – similar in height to modern wind turbines. The guyed towers were shown to kill about 100 migrants per year.
For perspective, this number is similar in magnitude to the number of night migrant fatalities at about 20 wind turbines. In other words, night migrant fatalities at one or two guyed public safety communication towers are equivalent to the number of night migrants killed at one or two small wind farms.
Even more interesting about the MPSCS towers is that they are also used by agencies that are entrusted with protecting birds. Both the FWS and the Michigan Department of Natural Resources are listed as members of the MPSCS and use the towers as part of their agency communications.
The MPSCS fatality estimates made by Curry & Kerlinger do not include birds killed during the non-migration seasons, so the estimate of 11,000 birds killed by these towers per year is undoubtedly less than the annual total.
Various other state and federal agencies, such as the U.S. Forest Service, also use these towers, and each tower has been licensed by the Federal Communications Commission (FCC) through the National Environmental Policy Act process.
And Michigan is not the only state encountering this problem. For example, in Ohio, the Multi-Agency Radio Communication System (MARCS) has about 250 towers, some of which are taller than 500 feet and have guy wires.
These towers are also used by the FWS, as well as by the Ohio Department of Natural Resources – the state agency entrusted with protecting birds. Using the same methodology of the Curry & Kerlinger studies in Michigan, it is possible that the MARCS towers kill about 15,000 migrating birds – perhaps more – per year in Ohio.
Most states already have public safety systems that have thousands of towers, many of which will be used by federal and state wildlife agencies. Together, these towers likely kill more than 100,000 migrants per year and perhaps more than are currently killed by wind turbines.
Other publicly funded towers are also likely to kill birds. Hundreds of public radio and television towers broadcast signals across the U.S., and some are taller than public safety towers.
Unfortunately, it is purely speculative to say how many birds are killed by public broadcasting towers because such towers have never been thoroughly scrutinized by the wildlife agencies.
It is also interesting that in the 13 years since the FWS released its interim wildlife guidelines for siting and building communication towers, it is likely that more than 1,000 public communication towers have been erected in the U.S.
To date, Curry & Kerlinger's study in Michigan appears to be the only one conducted at publicly owned or funded towers, despite the fact that fatalities at communication towers have been reported hundreds of times since the 1940s.
Overall, 6.7 million birds per year are estimated to be killed at public and private communication towers in the U.S., yet no pre- or post-construction studies are required as part of the federal licensing of towers.
Now that peer-reviewed and reliable estimates of fatalities at publicly owned and funded towers are available and show that large numbers of birds are killed at these facilities, it will be interesting to see if federal and state agencies are subject to the same laws and standards as the wind industry or if they are exempt from those laws.
Paul Kerlinger, Ph.D., is senior scientist and principal at Curry & Kerlinger LLC, a consulting firm specializing in bird and bat issues. He can be reached at (609) 884-2842 or firstname.lastname@example.org.