As fossil fuels become scarcer and more expensive and global climate change looms, the world is turning to alternate energy sources. One particularly popular source is wind power, in which giant windmills (or wind turbines, as the industry calls them) can generate renewable power. But that power does come at a price—turbines have been known to kill many species of birds and bats. Judd Howell, a biologist for engineering consulting firm HT Harvey and Associates in northern California, explains how scientists are trying to prevent these deaths.
What kind of scientific work do you do?
“For the past four years, I’ve been working with HT Harvey on wind energy and wildlife projects. Basically, I’m looking at the effects of wind turbine development on birds and bats. We’re working with companies on post construction fatalities.”
What have you found out about how wind turbines affect birds and bats?
“I did a two year radar study on bats and birds, looking at the volume of birds/bats flying through airspace. I was trying to find out how technology works together (radar, night vision, acoustic detectors). Also, I wanted to know if we could determine rates of fatalities based on numbers of animals flying through airspace. One thing we did find: nocturnal migratory birds were flying well above where the blades were rotating. Our data and other surveys showed a correlation between spatial relationship of roost trees and bat mortalities.”
Was the data from your survey surprising?
“Looking at these modern, bigger turbines; the surprise has been the bat fatalities. There were almost as many bat fatalities as birds. We’re doing a lot of work on trying to find ways to reduce bat facilities. Part of it this is curtailment, cutting in at higher wind speeds, because bats are flying at lower wind speeds. Also, ultrasonic noise makers interfere with bat’s sonic communication.”
I’ve noticed modern turbines turn more slowly; does that help bats?
“The RPMs are slow, but the tip speed is still 180 mph. The thing that gets the bats is barotrauma. They experience decompression around the blades, which causes damage to the lungs.”
How did you get into this?
“I first got involved with wind and birds in 1987. I wrote up a proposal to study Altamont Pass (an area near San Francisco used for wind turbines), and the company asked me to work in the Montezuma hills (another area near San Francisco). It’s been a good ten years’ worth of consulting work. I got to do some groundbreaking stuff: characterize what was out there. I worked on bird perching studies, and first painted blade study (where the blade is painted to increase its visibility).”
Judd Howell is a senior associate ecologist at H. T. Harvey & Associates. Previously, he was Director of the U.S. Geological Survey (USGS) Patuxent Wildlife Research Center, where he was responsible for the management of a broad, multi-disciplinary program of biological research, inventory and monitoring, and information management. While at USGS, he supervised research scientists in California and Arizona in numerous national parks, such as Yosemite, Redwood, and Channel Islands, as well as universities including the University of Arizona and UC Davis. Howell conducted wildlife research in many areas, including studies that laid the framework for the bobcat, gray fox, and coyote research program at the Golden Gate National Recreation Area. Howell received his PhD from UC Berkeley in wildlife ecology, an MS in zoology from Arizona State University, and a BS in zoology from Montana State University.