22 July 2009

Clark Fork Ospreys at Grant-Kohrs Ranch National Historic Site

 What a special day in the Park!  US Fish & Wildlife biologists are helping monitor the clean-up efforts on the headwaters of the Clark Fork River, which wends its way 310 miles through Montana and Idaho, eventually converging with the Columbia  River  and making its way to the Pacific Ocean.  Heavily polluted by upstream mining in Anaconda, Montana, about 20 miles south of Grant-Kohrs Ranch National Historic Site, the Clark Fork River died.  Chris Kronberg, graduate student at The University of Montana, wrote his graduate thesis, Biological Effects of Water Pollution in the Clark Fork River, on the river's comeback in 1983.  Efforts to maintain a healthy river ecosystem are still being monitored 26 years later.

This afternoon, the US Fish & Wildlife biologists were studying Osprey fledglings from nests located along the first 30 miles of the Clark Fork to determine what, if any, contaminants are present in the water.  Osprey live and nest near water sources, since at least 90% of their diet is fish.  Testing the fledglings, who are depending upon its parents for food sources brought to them, provides a good measure as to a water body's quality of health.

At Grant-Kohrs Ranch NHS, we learned another powerful and sad lesson.  The ranching livelihood plays a significant role throughout Montana, including Deer Lodge, 30 miles west of Helena and just west of the Continental Divide.  Hay, necessary for a herd's winter survival, is baled with orange, plastic netting that is often and regrettably left laying about in fields after being cut from the bales.  Osprey retrieve this material and use it in nest-building.  When the biologists went to retrieve the three fledglings, they discovered two fledglings died in the nest due to entangling themselves and being strangled by that orange netting.  Wildlife often demonstrates the effects of human pollutants; happily, we learned that the test results from all of the Clark Fork River Osprey fledglings showed 0 pollutants.  Now, the three sledge ponds located upstream in Anaconda are telling a different story, but they are doing their jobs of the keeping the pollution out of the river.


Only NPS unit dedicated solely to ranching

Unhappy Osprey parent circling the nest

U.S. Fish & Wildlife biologists retrieving fledglings for Clark Fork River survey 

Preparing for weighing

Two Osprey fledglings strangled on baled hay netting

Student workers clearing fields of plastic netting

Biologists removing plastic netting from the nest

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