Volunteer Vanessa Greene has been at it for almost 20 years
ECM Staff Writer
“Hear that?” asked Vanessa Greene of the thick chirping coming from the nesting platform. “She’s telling us ‘Back off,’” Greene said, keeping her eyes averted from the wary female osprey.
It was tempting to look.
Indeed, five osprey on a recent day near Golden Lake in Circle Pines were visible at once, males clutching fish in talon and beak to lure the coy female, all recently returned to Minnesota from wintering grounds in Mexico, Central and South America.
“Ospreys attract other osprey,” said Greene, binoculars dangling from her neck.
They attract people, too.
Greene, of Minnetonka, is the presiding spirit of the Twin Cities Metro Osprey Watch. She has spent almost 20 years observing and working with ospreys and to a degree expresses puzzlement why the broad-winged bird so mesmerizes her.
“I’m spending my life’s saving to do this,” Greene said of monitoring nesting sites in eight metro area counties.
“Mostly I’m driven by passion. I just really want to know,” Greene said.
The story of the return of the osprey to the metro is compelling.
Although originally native to the area, it’s believed the effects of DDT and the loss of habitat — the big, dead trees ospreys like to nest in — shooting and other factors led to the collapse of the local osprey population.
By the mid-1980s no ospreys were nesting south of Mille Lacs County, it’s believed.
But an osprey reintroduction program by the Three Rivers Park District (formerly Hennepin Parks), University of Minnesota Raptor Center and others in which osprey chicks from northern Minnesota were relocated to metro sites has proven successful.
By September 2002, some 270 wild chicks had fledged from 31 nests. Greene was hired in 1995 to work in the chick program, only leaving the park district a few years ago.
Last year, Greene and other monitors determined that there were 80 occupied osprey territories in the metro area. That is, areas where at least two birds showed nesting activities.
Eggs were laid in 73 metro area osprey nests, with 56 nests producing at least one chick.
Ospreys form population clusters. Clusters exist in Anoka/Ramsey counties, Hennepin County — at the Coon Rapids Dam — the Bayport area, Wright County, with a few nests in the Prior Lake area.
Other nests are scattered about the metro, including the city of Columbus.
Many ospreys nest on man-made structures — platforms on poles — but also on towers and other structures.
The birds are known for using lost mittens, stocking caps and other less traditional materials in building their nests, which, over time, can grow to weigh as much as half a ton.
Osprey males assist females in incubating eggs, some relishing the job more than others.
“Some males are very nervous when they sit there,” Greene said.
Once hatched, osprey chicks leave the nest after about eight weeks. “They’re still dependent on parents for quite awhile,” she said.
Greene has observed male ospreys feeding chicks as late as September.
Ospreys are identifiable by two-tone coloration — brown on top, white on the bottom — with white heads and dark eye stripes.
Their wingspans can reach six feet.
Osprey feed almost exclusively on fish.
Unlike bald eagles which grab fish near the surface, osprey, feet first, plunge into the water and may go several feet deep to catch a fish.
According the Minnesota Department of Natural Resources, studies have shown when fishing is good ospreys may catch a fish seven out of ten attempts. The birds are strong enough to pull a two-pound fish out of the water.
While eagles sometimes try to wrestle catches away from osprey, a more serious threat is posed by Great Horned Owls, capable of killing osprey adults and chicks alike, Greene said.
The range of the osprey is the globe itself, the bird found on every continent except Antarctica.
But the data Greene fills her notebooks with is the history of pairs and individual osprey, their successes, failures, disappearances.
One recent morning near Golden Lake Greene peered through her powerful spotting scope, through the heat shimmer, for a leg band on a male osprey attempting to woo a female sitting amid a scattering of sticks on a nesting platform not far from Golden Lake Elementary School.
Osprey started nesting at Golden Lake in 2004.
A few years later, a male known as “PU” from his leg band ID paired with a female for five years at the site. “The kids loved that,” Greene said of the exclamatory name. But as of that recent morning PU was still a no show. And males are usually the first ones back.
Greene marvels at the vitality of ospreys.
“When I’m looking at a bird that’s 19-years-old, it’s amazing they’ve been gone to South America that many times,” she said. And the challenges the birds face in South America could be sharper than the ones found in America, she said.
There’s much to learn about ospreys, Greene adds. Ospreys serve as indicator species, reflecting environmental changes such as water quality, she explained.
Their habit of nesting in the open makes them ideal for study.
There are many things Greene would like to learn about osprey.
For instance, her observations have led her to suspect osprey are less monogamous than scientific literature suggests. And it’s only through long-term research, continual banding, can deeper understanding be gained, she argues.
“You’ve got 28 years of data — why stop?” she asked.
While Greene speaks of a passion for osprey, her background suggests other interests as well. She studied photography in college and believes her artist’s eye — her ability to detect small details — has proven valuable in her work with osprey.
Currently, Greene teaches pottery at the Edina Arts Center. Her pottery has been showcased in various shows.
“So people should come and buy my pots to support my osprey research,” she said with a smile.
Osprey Watch has a growing number of volunteers, but she obviously needs more help. “The goal is to create a powerful team of people out there watching these birds. And together we can put together an accurate story,” she said.
Greene doesn’t necessarily expect a large time commitment from volunteers. But she does place an emphasis on reliability.
As for her passion for osprey, perhaps it ignited on a lake out west years ago in watching an osprey strike the water a short distance away.
“I don’t know what’s so captivating about them. But I’m hooked,” she said. “And the more you know, the more you want to know.”
For information, email Greene at email@example.com or visit http://ospreywatch.blogspot.com.