Savannah River Ecology Lab began monitoring bird traffic at the city’s constructed wetlands in 2001 after the Federal Aviation Administration raised concerns about the site’s proximity to Augusta’s airport.
The wetlands, now part of the Phinizy Swamp Nature Park, were designed to reduce pollution from the nearby Messerly Wastewater Plant.
Although the wetlands improved water quality, the network of grass-filled lagoons also created a perfect habitat for redwing blackbirds and other migratory species.
In a new paper, ecology lab scientist Bobby Kennamer said that the use of airboats to crush and flatten vegetation each fall has significantly reduced the area’s appeal to birds.
Scientists observed as many as 15 million blackbirds moving through the area annually in the first few years after the wetlands were completed.
Thinning of cattails that the birds use as roosts helped reduce their numbers but spawned an increase in waterfowl and wading birds, which can also pose hazards to aircraft, the paper said.
In 2005, researchers launched a pilot program to crush the vegetation with airboats just as the blackbird migration begins.
“This work successfully demonstrated that with thoughtful wildlife hazard management, including the consideration of novel techniques, it may be possible to mitigate large-scale undesirable wildlife attraction associated with certain land-use activities,” he wrote.
Crushing the plants in the fall keeps the area nearly bird-free through winter, and the plants regrow in spring.
An important facet of the program, he wrote, was its success at controlling blackbird numbers with nonlethal means.
According to the FAA, bird collisions with aircraft have increased dramatically, from 1,804 in 1990 to more than 10,000 in 2011.