Program helps increase population of endangered birds
October 18, 2012
FORT JACKSON, S.C. -- Autumn means many things to many people -- football season, changing leaf color, the state fair and cooler temperatures. But to biologists in the Directorate of Public Works Wildlife Branch, autumn has a special meaning -- red-cockaded woodpecker translocation time has arrived.
Only found in old growth longleaf pine forests of the Southeastern United States, the red-cockaded woodpecker, or RCW, is a federally listed endangered species. This small bird, measuring about 7 inches in length, was given full protection with the passage of the Endangered Species Act in 1973.
Habitat loss is the reason the RCW is listed as an endangered species. Its habitat is the open and mature pine ecosystem, which once covered an estimated 90 million acres across the Southeast at the time of European settlement.
Today, only about 3 million acres of this ecosystem remains, primarily due to deforestation from agriculture, urbanization and over-harvesting of old growth pines.
Translocation of juvenile RCWs is one of the many management tools biologists use to help increase RCW numbers and recover declining populations. This technique involves moving one or more juvenile RCWs between or within populations to introduce the birds to suitable unoccupied habitat or to supplement the number of RCWs already living in an area.
Translocations can also increase genetic diversity in critically small populations.
"Technically, there are two types of RCW translocations we use," said Nicole Hawkins, DPW wildlife biologist. "One is where a solitary female juvenile is moved to a location occupied by a solitary male. The other is where an unrelated male and female juvenile are moved to an unoccupied area of suitable habitat. The goal of both translocation types is to establish a new pair of breeding RCWs. It's like eHarmony for RCWs."
All translocations are conducted in accordance with strict management guidelines established by the U.S. Fish and Wildlife Service. These guidelines provide the time of year for translocation, establish the qualifications for where RCWs may be captured, detail what constitutes suitable habitat where RCWs can be moved, and give specific rules for capturing, releasing and monitoring the RCWs.
In order to capture a juvenile RCW, monitoring must be conducted to ensure the bird is roosting in a cavity tree, as it's impossible to capture open roosting birds. RCWs are typically captured at dusk using a specially designed mesh capture net on a telescopic pole.
"The targeted juvenile is observed from a distance to ensure it enters its roost cavity," Hawkins said. "About 10 minutes are allowed to pass so the bird can settle down for the night, then the capture net is quietly raised to cover the roost cavity entrance. A few taps on the tree trunk generally spooks the bird out of the cavity and into the net.
"Once captured, the RCW is placed in an enclosed box and transported to the relocation site. A trained wildlife biologist or technician climbs the new cavity tree and places the RCW inside for the night. A wire screen is used to cover the cavity entrance so the RCW does not escape. The next morning the screen is removed so the bird can exit, begin exploring its new territory and meet its potential mate."
Since 1994, the Wildlife Branch has captured and translocated 79 RCWs. Some of these were captured off post and relocated to Fort Jackson, while others were translocated within the post's RCW population.
Approximately 52 percent of these translocated RCWs have become breeding birds. These results are similar to other military installations in our physiographic region.
"This fall, our goal is to capture two juvenile females and move them to two solitary males," Hawkins said. "In addition, we hope to capture two unrelated pairs and move them to two unoccupied areas on post that have suitable habitat and roost cavities. All these RCWs will come from our own Fort Jackson population, and will hopefully increase the number of potential breeding pairs for next spring's RCW nesting season."