Posted: July 25, 2008, 5 a.m. EDT
Photo Courtesy Michael Avery
Quaker parrots feed at a study site in Florida's Miami-Dade County. |
The sight of a quaker parrot (also known as a monk parakeet) in their neighborhood may bring smiles to the faces of many bird lovers. For power companies, which must increasingly deal with these birds’ stick nests on their electrical towers, the surprise isn’t so welcome.
“When [the quaker parrots] build their nests in these structures, a lot of times the branches and the sticks get wet from the rain and come in contact with components and cause a short circuit,” said Michael Avery, research wildlife biologist with the U.S. Department of Agriculture’s National Wildlife Research Center. Avery added that these short circuits can cause power outages and fires.
To reduce the woes of companies dealing with electrical problems caused by the nests, Avery and his research team are testing avian contraceptives to control South Florida’s population of feral quaker parrots. His findings will appear in next month’s Journal of Wildlife Management.
Avery’s research is a response to the growing numbers of feral quaker parrots in South Florida and other parts of the United States, where the birds were introduced in the 1960s through the pet trade. Since at least the late 1980s, the birds have nested on these electric utility facilities, according to the journal article “Diazacon Inhibits Reproduction in Invasive Monk Parakeet Populations” by Avery and colleagues Christi Yoder and Eric Tillman.
Before deciding on the contraceptives, Avery said, his research team looked at several methods to deter the quaker parrots from nesting in the electrical facilities, including sound and visual deterrents; as well as barriers or tactile techniques.
“None of those really seemed to make a dent in them,” Avery said. “The birds are very resilient and don’t seem to mind any of those things that we tried.”
Avery said he and his team didn’t like the idea of increasing mortality among the birds, which would be unpopular and hard to implement. Avian contraceptives are nonlethal, and Avery said they had been successful in previous tests.
After they performed trials that yielded positive results at the National Wildlife Research Center facility in Gainesville, Fla., the team headed to Miami-Dade County, Fla., in 2006 and 2007, where quaker parrots had caused problems for Florida Power & Light Company.
The team decided on the contraceptive DiazaCon, which inhibits reproductive hormone production. At each of its nine Florida study sites, researchers set up feeders for the birds and exposed the quaker parrots to the contraceptive for 10 days. Avery said they used sunflower seeds as bait and coated the seeds with DiazaCon.
The results proved successful. Avery and his team found an almost 70 percent reduction in the nest productivity of the parakeets.
Not every part of the experiment proved perfect, however, with birds such as doves and pigeons also visiting the feeders.
“In most cases, there was very little nontarget use of the base sites,” Avery said, “but there were some where there was quite a few.”
To prevent accidental ingestion by other birds, Avery and his team developed and tested a feeder this year that theoretically only quaker parrots can get into, he said. While some other species did eat the untreated seed during the tests, the numbers were very few.
“We need to make sure we have a good, reliable method of administering [DiazaCon] so nontargets aren’t exposed,” Avery said. “That’s going to be our goal.”
Now, Avery hopes to register DiazaCon with the Environmental Protection Agency as a contraceptive for controlling the quaker parrot population.
Though Avery said he hasn’t received a direct response on the issue from the bird community, he said comments from meetings and discussions have been positive.
“Generally, people are supportive because we’re dealing with a non-native species and we’re using a tool that’s not lethal,” he said.