Bald Eagle Populations Along the Mississippi Grow
By Jason Hoppin, Pioneer Press, St. Paul, Minn.
May 16–Circling with malicious intent, the bald eagle makes a pass at a pair of ducklings floating near the Mississippi River shore.
Ignoring a crow’s airborne harassment, the eagle draws in its wings and angles toward the water. The ducklings dive for protection, but it doesn’t work. As one swims toward safety, the other writhes in the eagle’s talons as the big raptor flies away.
They don’t call ‘em sitting ducks for nothing.
This scene was rare a few decades ago, when the national bird was on the verge of extinction. But bald eagles have rebounded in Minnesota and elsewhere, prompting the federal government to consider removing the bird from the list of threatened and endangered species.
Still, some researchers and raptor lovers aren’t taking the comeback for granted. On Tuesday, a group of scientists pushed off from a South St. Paul boat launch to study contaminants in baby eagles as a way to look at how the rest of the ecosystem is doing. It’s part of the National Park Service’s Vital Signs program, where scientists at 270 national parks are studying the country’s ecological health.
“We should congratulate ourselves for bringing bald eagles off the endangered species list, because it was only in the ’70s that we found that DDT and some of these other contaminants really did hurt their population,” said Bill Route, coordinator for the Great Lakes Inventory and Monitoring Network, which is studying contaminants in nine national parks in the Great Lakes region.
“But we now have these new things, like PFOS (perfluorooctane sulfonate) and fire retardants, and we don’t know what the effects of these things are on bald eagles or on ourselves,” Route said.
Working off nest maps provided by Ramsey County, and with the help of Audubon Minnesota and the state Department of Natural Resources, park service officials eventually will climb into about 50 nests throughout Minnesota and Wisconsin, including six in St. Paul.
Their mission is straightforward: Ascend into the swaying forest canopy, crawl into sprawling nests that can weigh as much as a ton and retrieve and test 6-week-old eagle chicks while ignoring the caws of some very agitated parents.
The first step is getting up there, which is where Giacomo Renzullo and Jim C. Spickler, two young scientists from Arcata, Calif.-based Eco-Ascension Re-search and Consulting, come in.
The key word is “ascension.” Both are skilled climbers who use an angler’s dream to get into the nests — a fishing reel fixed to a crossbow.
A blunt arrow is shot over a high cottonwood branch. Renzullo and Spickler use the fishing line to pull a rope over the branch, and then shimmy 70 feet or more into the canopy. The two literally get into the nests to collect the chicks.
And what’s it like to stand in an eagle’s nest?
“Here, it’s great,” Spickler said, explaining that Alaskan nests are lice-infested. “The nests are big. Some of them you can lay across.”
At six weeks (give or take a few days), eagle chicks are agreeable. Though already bigger than a newborn baby, they can’t fly yet and sit indifferently on the ground without fleeing. Blood is drawn; feathers are collected, and the birds are weighed and measured before being put back.
The blood is tested for mercury, lead, PCBs, DDT and a derivative, DDE, a fire retardant called PDBE (polybrominated diphenyl ether) and PFOS, a chemical produced by 3M recently found in drinking water in Oakdale and Lake Elmo and fish caught in the Minneapolis Chain of Lakes.
To Route, the big surprise last year was finding DDT in several eaglets, mostly near the Apostle Islands National Lakeshore. But it was also found in a sample taken from a chick at Pig’s Eye Lake.
Banned in the 1970s, the DDT should have broken down by now, and Route speculated the St. Paul finding is likely from a recent discharge — perhaps someone who found an old pesticide in his garage and dumped it into the sewer system.
The park system also is studying PFOS. Last year’s results aren’t available yet but are expected within weeks.
In 1963, there were only 417 breeding pairs of bald eagles, according to the U.S. Fish and Wildlife Service. By preventing birds from producing enough calcium to form strong eggshells, the pesticide DDT almost killed off one of the country’s most enduring symbols.
On Monday, the U.S. Fish and Wildlife Service put the number of breeding pairs at 9,789, the highest level since World War II, including 1,312 pairs in Minnesota — tops in the nation.
The Fish and Wildlife Service is finalizing steps that could lead to the bald eagle’s delisting, which is widely expected. A final decision should come before a court-appointed deadline of July 29.
“We’ve met the goals. The bald eagles have been flourishing,” Fish and Wildlife Service spokeswoman Valerie Fellows said.
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