BISMARCK, N.D. (AP) -- Despite a threatened lawsuit by a wildlife advocacy group, federal officials are spraying chemicals on 4,500 acres of cattail-infested wetlands in North Dakota to kill the preferred habitat of blackbirds that feast on sunflowers.
Aerial spraying of cattails in 16 North Dakota counties is scheduled to be completed early this week, at a cost of about $175,000, said Phil Mastrangelo, the North Dakota director of the federal Agriculture Department's Wildlife Services agency.
The program targets only cattails on private land and is free to sunflower farmers. More than 60,000 acres of cattail marshes in North Dakota have been destroyed since 1991 to try to keep blackbirds from attacking nearby sunflower fields, the agency says.
WildEarth Guardians, based in Santa Fe, N.M., alleges the program violates the federal Clean Water Act by applying herbicides on wetlands. The group notified the USDA in April that it will sue in federal court.
Wendy Keefover-Ring, a WildEarth Guardians spokeswoman in Bozeman, Mont., said her group is still gathering information for the lawsuit.
"We're still going to file," Keefover-Ring said Monday.
Mastrangelo said the agency is complying with all regulations. He said rules that cover cattail spraying are to be rewritten in 2011.
The herbicide used to kill cattails is approved by federal regulators.
The USDA estimates blackbirds eat more than $10 million worth of sunflowers each year in North Dakota, which accounts for about half of the nation's sunflower production. Some 70 million blackbirds come through the Northern Plains each year, including about 6 million that stop in North Dakota, biologists say. Each blackbird can eat about an ounce of sunflower seeds daily.
Blackbirds nest, loaf and roost on the fuzzy-topped weeds with reedlike leaves.
The government spent about $166,000 to spray from the air 3,700 acres of wetlands in North Dakota and 99 acres in South Dakota last year, Mastrangelo said. No applications were received from South Dakota this year, he said.
Cattails cover some 600,000 acres of wetlands in North Dakota. Biologists say blackbirds typically feed on farm fields within five miles of their roosts in cattail stands.
Wetlands treated with the herbicide are typically free of cattails for about five years, the USDA says.
On the Net:
Wildlife Services: http://www.aphis.usda.gov/wildlife(underscore)damage/
WildEarth Guardians: http://www.wildearthguardians.org/
Copyright 2009 The Associated Press.