Osprey nests are a common sight near rivers, lakes and bays around here. If you look closely with binoculars, you might notice some of these large raptors like to line their nests with discarded baling twine or fishing line. The problem is it can kill them. Now wildlife biologists are working with ranchers and at boat ramps to keep the attractive nuisance out of the ospreys' clutches. Correspondent Tom Banse reports from Missoula.
University of Montana professor Erick Greene has surveyed osprey nests in his home state and parts of Washington, Oregon, large portions of Idaho and Wyoming. In all those places, he discovered nests festooned with brightly colored plastic twine.
Greene: “Basically, wherever you’ve got agriculture, hay fields, livestock – which is a lot of the West – you have baling twine, which is used to tie up hay bales, and you have ospreys.”
Greene says for unknown reasons, the fish hawks are particularly fond of soft, frayed twine. They use it in place of lichens or grasses in their nests.
Greene: “Ospreys have a jones for this baling twine. I wish they didn’t.”
It’s sometimes a fatal attraction.
Greene: “It looks as if anywhere between 10-30% of osprey chicks and adults in some areas that are particularly hard hit are killed by this baling twine.”
The entangled raptors can suffer gruesome deaths by strangulation or starve because they can’t fly off to fish. That is, unless someone comes to the rescue… or better yet gives a nest what Greene calls a preventive “haircut.”
I tag along as Greene enlists a bucket truck and a crew of linemen from the Missoula Electric Cooperative. We arrive at a nest with chicks. It’s on top of a power pole in the middle of a ranch by the Clark Fork River.
Greene: “This is a nest I've been worried about for years. It has killed a lot of ospreys over the years. This is going to be a good one to clean up.”
Lineman George Porter and I go up to the nest with scissors. Strands of orange string drape from the wide bowl of sticks like Christmas tinsel.
Tom Banse: “George, it looks like the osprey tied knots here!”
Porter: “That’s basically what it looks like, all tangled. Yeah, they definitely use it to hold everything together.”
Tom Banse: “Looks like they went to Boy Scout school.”
Tom Banse: “There’s all kinds of twine. That was a piece of black nylon rope that they added.”
Tom Banse: “In the background, you can hear the osprey pair chattering a little. But they’re being pretty quiet and keeping their distance from us. I don’t think they can figure out what’s going on here.”
The preferable solution of course would be to keep twine and fishing line out of nests in the first place. In Idaho, the state Fish and Game Department along with local partners are placing periscope-shaped recycling bins for fishing line at boat ramps. State wildlife biologist Beth Waterbury also worked on setting up a baling twine pick up and recycling program in her area, the upper Salmon River valley.
Waterbury: “It’s a logical solution and I think it is going to make a difference for the incidence of entanglement.”
In western Montana, student researcher Amanda Schrantz did public outreach to farm groups and individual ranchers. She says many of her contacts didn’t have any idea about the lethal effects of discarded twine or the pressing need to collect and store it out of sight.
Schrantz: “Ospreys will go great distances to pick up this baling twine. Even though we don’t know why, they are. You kind of have to have 100 percent cooperation with this.”
Schrantz says if just one ranch or dairy leaves twine in its fields, the ospreys will find it.
In Oregon’s Willamette Valley, a private plastics recycler accepts used baling twine and hay wrap.
“We recycle about a quarter million pounds per month of baling twine,” said the co-owner of Agri-Plas, Allen Jongsma. He said used twine can be melted down to make new baler twine or automotive parts.
A different company, fishing tackle maker Berkley, recycles recovered monofilament fishing line into artificial reef pieces.
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