Wisconsin ospreys spread wings to Iowa
When a species recovers in Wisconsin and is removed from the endangered and threatened lists, it's worthy of celebration. When the species so thrives after delisting that its young are used to seed the recovery in another state, it's not just the...
When a species recovers in Wisconsin and is removed from the endangered and threatened lists, it's worthy of celebration.
When the species so thrives after delisting that its young are used to seed the recovery in another state, it's not just the highest level of conservation success -- it's diplomacy. Even if it involves turning
Wisconsin fish hawks into Hawkeyes.
Five osprey nestlings were captured in nests in Barron and Washburn counties earlier this month and are now testing their wings in their new home near Dubuque, Iowa.
"We enjoy spreading the success," said Pat Manthey, avian ecologist with the Wisconsin Department of Natural Resources.
It's part of a Wisconsin program started in 1999 to help Iowa re-establish an osprey population.
Sometimes called fish hawks, ospreys are specialized birds of prey that hover over water before plunging in feet first in an attempt to grasp prey. The birds have a handsome black eye stripe, about a 5-foot wingspan and weigh 3 to 4 pounds.
But even in fish-rich environments, ospreys were devastated by the use of pesticides such as DDT during the 1950s and '60s.
Wisconsin placed the osprey on the state's endangered species list in 1972.
After DDT was banned, and as humans helped by building nest platforms, ospreys began a steady increase in Wisconsin. The number of nesting pairs of ospreys in Wisconsin went from 82 in 1974 to 527 in 2011.
The osprey was reclassified from endangered to threatened in Wisconsin in 1989 and was removed from the threatened list in 2009.
Ospreys nested in 57 of Wisconsin's 72 counties last year. Eighty percent of the nests were on man-made structures, including power transmission platforms and ball field lights. The sites give the ospreys safety from predators such as raccoons.
The Wisconsin ospreys produced 531 young in 2011, according to the DNR.
In a sample of successful Wisconsin osprey nests last year, 47 percent had one nestling, 47 percent had two and 6 percent had three.
It's those last two nest types that Ryan Magana, DNR regional ecologist in Spooner, looks for in an aerial survey.
"We're looking for 5- to 7-week-old nestlings," Manthey said. "At this age, they are fully feathered and can tear apart food by themselves."
After Magana identified five nests in early July, Manthey traveled to northern Wisconsin and met David Evans of Duluth and Pat Schlarbaum of the Iowa DNR.
Evans, an expert climber and experienced bird handler, donned his hard hat and climbed to the five nests.
Falling is always a danger, but when the object of the climb is to remove a young raptor from its nest, there is also a danger from on high.
The adult ospreys swooped at Evans and tested his headgear, Manthey said.
Evans plucked one chick out of the nest and banded any left in the nest with identification from the U.S. Fish and Wildlife Service.
The singled-out chick was carefully lowered to the ground in a padded bag and banded. The Iowa-bound birds get two leg bands, including one with large, easy-to-read codes.
Once all the birds were collected, they were fed a "meal of yummy fresh baitfish," Manthey said, and left in a secure building to rest for the night.
The next morning Schlarbaum transported the birds to the Raptor Center at the University of Minnesota for health exams and another meal of fish.
Their new digs in Dubuque are an 8-by-8-by-8-foot "hack" box or cage. The birds are fed in a manner that does not allow them to see humans. When they are big enough to take their first flights, the cage will be opened and they can fly to freedom at the site they now consider home.
Manthey said ospreys imprint on the area where they take their first flight.
Ospreys are expert fish catchers. Manthey said the young will instinctively start to catch fish once they fledge.
Sometime in fall, the birds will migrate to Central or South America, where they will spend one to three years. When they return to the Midwest, they should establish a territory in Iowa.
Thanks to the program, Iowa now has 15 nesting pairs of ospreys. All costs of the program have been paid by Iowa agencies.
The five Wisconsin ospreys transferred to Iowa this month probably are the last of the program, Manthey said.
"It's been a huge success," Manthey said. "The fact that it has spread to our neighboring state just makes it even better."