A steady north wind rakes across the limestone bluffs of East Tennessee, driving a cold, dark chop down the long reach of Chickamauga Lake. Decembers here hold a dense, heavy humidity that anchors the frost to the dried switchgrass along the mudflats. Out on the main channel, rafts of gadwalls and mallards ride the swells, their dark shapes rising and falling against the vast expanse of open water. Ice lines the clay banks where the summer pool receded, leaving a white rim along the drowned timber. The cold is thick, smelling of wet earth and river silt, carrying the sharp scent of winter cedar from the ridges above.
Along the skeleton fingers of the lakeside sycamores, the winter birds take their perches. They show themselves in early December, heavy shapes against the mottled bark, silhouetted where the ridgelines drop toward the water. These are the bald eagles, their white heads catching the pale winter light before the clouds close in. They sit over the channel from dawn until the late afternoon shadows freeze the coves, staying through the deep freeze of January and into the late winds of February. Some flap low over the open water on stiff, broad wings, while others look down from the crowns of the dead oaks that stand flooded in the shallow bays.
Farther north, the hard freezes of the upper continent close inland lakes and seal off the shallow bays where waterfowl forage. Here, the massive concrete barriers of the Tennessee Valley Authority keep the river moving. Below the spillways, the churning tailwaters stay open, boiling with a constant current that turns up stunned shad and concentrates migratory ducks. The reservoirs hold immense volumes of water that insulate against the mountain freezes, providing an accessible supply of food. Driven by the closing of those northern waters, breeding populations of eagles move down the river corridor to winter along these engineered lakes.
Within the memory of people still farming these ridges, the river timber stood empty of these birds. The mid-century crash, driven by DDT-induced eggshell thinning and reproductive failure, was compounded by shooting and the loss of shoreline habitat. The species has since recovered, and the birds return to these artificial coastlines every winter.
At Watts Bar, along the sweeps of the lower lake where the Clinch River meets the Tennessee, watchers park on the gravel pull-offs with binoculars propped against steering wheels. Below Chickamauga Dam, the views open up from the high embankments where the wind shears off the concrete and bites through wool gloves. A viewer spends hours watching a single distant knot on a sycamore branch, waiting through the dim morning for the moment the shape detaches itself and drops into a low, hunting glide. Success requires a cold patience, staring into the glare of the channel until the eyes water from the wind.
Below the lock walls, the turbine hum vibrates through the limestone bedrock while the massive steel gates regulate the flow of the entire watershed. Out in the tailwaters, an eagle drops its talons into the white foam of the discharge. It lifts a struggling gizzard shad from the current and flies toward the roof of the concrete powerhouse.