OKLAHOMA — It is quite common to hear the chirp of birds along the McClellan-Kerr Arkansas River Navigation System. Recently, however another type of bird, a helicopter, could be heard whirring over the MKARNS.
For the first time, the U.S. Army Corps of Engineers, Tulsa District used a helicopter to spray herbicide on four Interior Least Tern islands along the navigation system.
The Interior Least tern is an endangered migratory bird that comes from Central and northern South America to use barren or sparsely vegetated sandbars along the Arkansas River, among other river systems, as nesting grounds during the summer months. Since most of the sandbars along the MKARNS are lush with vegetation, they must be sprayed with herbicide to make them suitable habitat. In the past, the Corps has sprayed by boat and this process could be very time consuming and expensive. Using a helicopter was a significant savings of both time and money.
"Spraying by helicopter gave us a 45 percent cost savings in labor and material," said Stacy Dunkin, biologist with the Tulsa District. "We also were able to do in one day what normally takes us at least three weeks."
Compared to spraying by boat applying the herbicide by air was also much more effective and required less herbicide to be used.
"The efficiency at which the helicopter applies the herbicide allows us to cover more area and use two thirds less than we would by boat," he said.
The Corps used a special type of herbicide called Imazapyr Salt that is approved by the EPA to be used in and around water, Dunkin said.
Though the actual application of the herbicide by helicopter only took a few hours, the planning and logistics took several weeks. The contactor, AirPro, Inc. of Sallisaw, Okla., made arrangements for landing zones near each island, which included getting permission to access private property. The Corps of Engineers traffic control and security during times the helicopter needed to refuel and reload the herbicide.
One of the greatest logistical challenges was coordinating safety. In addition to having a Tulsa District boat and personnel onsite in the event of an emergency, the contractor arranged to have the Sequoyah County Sheriff's Office and a swift water rescue team on standby.
"Safety was a huge aspect of this project," Dunkin said. "A lot of careful thought and preparation went into making sure that contingencies were in place in case of an accident. We wanted to make sure that we were prepared."
It will take a few weeks for the herbicide to take full effect, but Dunkin is hopeful that it will provide excellent results and he plans to continue using herbicide and helicopters in the future.
"My goal is to keep the islands clear of vegetation, but I know from previous experience the vegetation will be back next year," he said. "We have considered other options, but using herbicide by helicopter is the most effective method for long term control of vegetation and it's also the most efficient and cost effective method."
Three of the four islands sprayed were built by the Corps of Engineers using dredge material and the fourth was an existing sandbar that was enhanced by the Corps to make it a more suitable habitat for the birds. The Corps is involved creating the habitat because dams, reservoirs and other changes to river systems in Oklahoma have eliminated most historic habitat for this endangered bird.
"Maintenance and creation of nesting habitat for the Interior Least Terns is mitigation for the operations of our flood risk management projects," Dunkin said. "Through consultation with the U.S. Fish and Wildlife Service, we are required to maintain the nesting habitats for the birds."
The Corps works diligently to maintain these islands, so the use of a helicopter by the Corps seems only fitting-- a bird helping birds.