Nature Meets Technology

Native birds nest on bridges and buildings on the downtown waterfront

Bridgeview Grill went out of business, but right now it’s a fun place to visit. Along the water as it flows past the university, the building is home to a thriving colony of barn swallows. Walk the docks that pass under Neyland Drive along the mouth of Second Creek, and these handsome birds will zip past you, showing off the band of white spots atop their forked tails.

The birds have built numerous nests on the lips of the steel girders beneath the University of Tennessee rowing facility. Unlike mockingbirds, barn swallows do not attack you for coming near their nests; they see you as a slow-moving obstacle and go about their business of gobbling insects from the air above the river and downtown to feed to their babies.

Nests are in varying stages. Some are new construction, others built atop and beside old nests. I saw several with five nestlings, eyes closed but feathers growing, the brood getting too big for the mud cup. In other nests, babies are too small to see except when they raise their heads to be fed. Some pairs looked to be starting a second brood.

In one nest were three young birds, eyes open, looking like they could make the great leap into flight any minute. There is no second chance for these swallows. Jumping before their wing feathers are grown means they are carp food. That this nest had only three occupants hints at a dark truth. The weakest one or two nestlings probably got pushed into the water by nestmates as the brood outgrew its nest. Baby birds found on the ground often get there by similar means, and they can be hard to rescue because they were weak and neglected to begin with. Life is sacred and profane.

Whizzing birds swooping in and out, twittering babies greeting parents and chattering adults drive such thoughts from mind as you stand amid this swallow colony.

It is not the only one downtown. Henley Bridge hosts a colony of cliff swallows. From the bridge you can see the birds diving in and out below you, but the nests can only be seen from below with binoculars. Like barn swallows, cliff swallows build nests from mouthfuls of mud, but their nest structure is more elaborate. The entrance is a tube protruding from a globe of mud built into a corner beneath the bridge. Cliff swallows do not have forked tails, but like barn swallows, they have rich blue, rust, and white markings. These two swallow colonies consume a lot of flying insects.

Below-deck repairs on the Henley Bridge should be done in fall and winter when the birds are in South America.

The presence of these colonies is a good sign for a river recovering from decades of pollution. Downtown, the river is actually a lake, flow rate determined more by the pool level of Fort Loudoun Dam than by the rivers that merge two bends upstream. At the peak of winter draw-down, the river almost shrinks to its natural, more rocky channel, but it never quite gets there.

The lake that looks like a river is also a hybrid of native and invasive plants and animals. Beautiful sycamores mingle with ratty banks of privet. There is a pretty berry thicket on the riprap along Volunteer Landing, but I think it is an invasive wineberry.

The city plans to establish a wetland along the South Waterfront, but what sort of wetland should occur on that unnatural shoreline is hard to say. It may be impossible to recreate a river wetland without natural flood cycles, and bottomland wetlands are typically much larger. Ospreys—lake birds—are nesting on the rail trellis. An eastern phoebe, a river bird, flits around the docks. Whatever they build, aquatic life will come, and while there is still room for improvement, all that life in the middle of the city is proof that efforts by Tennessee Department of Environment and Conservation, TVA, and industry to restore our waters is paying off.

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