>>Saving the Mississippi/Birds
North America’s breeding birds, half of which migrate on the Mississippi Flyway, have long been a barometer of the river’s ills. While Katrina’s lasting harm to them remains uncertain, what is clear is the link between the birds’ health and the river’s—in its entirety.
By Frank Graham Jr.
Distant thunderclouds flaring with explosions of silent lightning moved closer from the north and west as we cruised the great river above Vicksburg, Mississippi. Around the 18-foot open boat coiled the waters drained from half a continent, gathering speed and volume, aimed at the Gulf of Mexico, 485 river miles to the south. We were into the last days of August when Hurricane Katrina, still churning up the Gulf, had nothing yet to do with this region of the Mississippi.
Around our boat, least terns dipped low over ruffled waters. A half-dozen wood storks crossed the river from Louisiana’s subtropical forest, alternately flapping and gliding on their broad wings. Out of a murky rainsquall that suddenly engulfed us from the north wheeled the buoyant forms of black terns—breeders on northern lakes, now en route to their winter homes on warm seas, their diminishing numbers a mirror of this entire ecosystem’s uncertain future.
When Katrina smashed ashore last August 29, I was with a small group of environmentalists marooned in Vicksburg as the region’s airports shut down. We watched the storm’s advance on the Weather Channel. Then the power snapped off and the phones went dead. Safe at this distance from battering waves and rising floodwaters, we sat in our darkened hotel rooms and nibbled at a stale sandwich or a chocolate bar snatched from a counter just before the stores closed. The wind howled, and here and there a tree fell. By evening the surrounding countryside was eerily dark, the sky swept clear of stars and lighted aircraft, on the roads only the occasional startling flash from a passing police car.
To the south of us a world-class city had already collapsed. Some of our party would be going back to the unknown, perhaps to discover the loss of a friend, or a home in ruins. But because of our shared interest, there was also talk of birds. What happens to migrants as they encounter winds that are almost off the charts? Would the storm surge break through weakened barrier islands and marshland to wipe out remaining foraging and nesting areas? If so, would the wetlands recover? Some of these questions remain unanswered, even as we approach the 2006 hurricane season.
Long before Katrina made landfall, birds were warning of trouble in the Gulf and, indeed, all along the Mississippi River’s 2,340 meandering miles. The river and its numberless tributaries create the continent’s most diverse wetlands, an age-old magnet for more than half of the birds that breed in and migrate through North America. Mississippi River habitat has been drained, plowed, developed, dammed, and channelized. As a result, greater and lesser scaup, canvasbacks, and ring-necked ducks—proverbial canaries in the coal mine—are seeing long-term declines. Black tern populations have fallen sharply in the past four decades, while numbers of other birds on the river fluctuate because of the uncertain environmental conditions.
“Birds have been studied more intensively than most organisms, so they are good icons for alerting us as to what is going wrong in the system,” says Greg Butcher, Audubon’s director of bird conservation. “The plight of the ivory-bill, just by itself, indicates that we have been doing something wrong.”
In the Upper Mississippi River valley lie the seeds of the river’s degradation. Minneapolis marks the beginning of commercial navigation, and from there the struggle starts as the great meandering stream periodically refuses to jump through the hoops engineers fashioned for its control. A 300-foot-wide, 9-foot-deep navigation channel dredged by the U.S. Army Corps of Engineers is supplemented by 29 locks and dams, chopping 699 miles of the once free-flowing Mississippi into a series of “pools.”
Levees further restrict the river’s age-old course while isolating its main stem from much of the original floodplain—more than 25 million acres of rich sediments the river has deposited over thousands of years as it oscillated across the wide valley. Behind those manmade walls, homes and farms now spread over a floodplain that only a century ago nourished forests and wetlands congenial to wildlife. The altered landscape gives back to the river a mush of polluted runoff, farm contaminants, and an excess of nutrients that feed a seasonal “Dead Zone” covering between 4,500 and 8,000 square miles in the Gulf of Mexico.
Remnants of the floodplain forest, narrowed and fragmented in the upper valley, have lost nesting and foraging places for migrant and resident birds. Along various northern stretches of the river, good habitat is often restricted to islands and backwaters, which are buffered against predators, development, and other mainland disturbances.
Meanwhile, the Mississippi’s backwater channels fare no better than the mainstream. Dams on the tributaries trap both water and sediments, flooding or burying plants important to waterfowl. In some reaches, big trees also suffer. As cottonwoods and other forest giants die, more habitat disappears. Today the once-diverse forests are being replaced by willows and silver maples, fast-growing species that form monocultures and thus increase the forests’ vulnerability. “It’s largely a habitat problem,” says Mike Griffin, a biologist in Iowa’s Department of Natural Resources. “Marshes silt in. Light doesn’t get through to submerged plants like wildcelery that many waterfowl prefer. Terrestrial vegetation takes over.”
When I reached Jon Stravers in the days after Katrina, he was monitoring the movements of birds on a bluff in northeastern Iowa, high above the river. Among them was the red-shouldered hawk, a raptor of eastern and midwestern woodlands that is especially attracted to watercourses. Since 1982 Stravers, known widely as “Hawk,” has inventoried the nesting sites of red-shouldered hawks and bald eagles in the recovering forests of the Upper Mississippi for various government agencies and conservation organizations, including National Audubon. “Colleagues and I worked along a 500-mile stretch of the river, from Hastings, Minnesota, to Hannibal, Missouri, surveying the nests of red-shouldered hawks,” Stravers said. “When I started we knew of only four active nest sites in the region. Now we have 63 sites. This is important potentially in terms of the proper management of forests along the river because states in our region list these hawks as either endangered or threatened, or of ‘special concern.’ ”
Volunteer bird-banding stations in Iowa, manned by Stravers and others, are further reinforcing the river’s importance as a critical migratory flyway. “Here at our small banding station in McGregor, we’ve demonstrated the attraction to birds of this river system,” he reported. “We recaptured a peregrine falcon banded along the Tanana River in Alaska four years earlier, and another peregrine banded only three months earlier in Greenland. They had converged here from points almost 5,000 miles apart to use the Mississippi on migration. And we caught a Cooper’s hawk banded four years earlier at Veracruz, Mexico—1,750 miles directly south of us. I like to imagine the migration routes of those three birds forming a perfect Y with the banding station.”
Near St. Louis, where the Mississippi and Missouri meet, the augmented river breaks free of its lock-and-dam confinement. Here it picks up speed as it moves on through the wide, rich, and troubled lower valley, where forests once grew so exuberantly in the sultry climate and marvelously fertile soil of the original floodplain.
The forests began to succumb to loggers in the late 1800s, though some survived here and there in dense groves until after World War II. They had been home to the “ghost birds”—ivory-billed woodpeckers, Bachman’s warblers—and their persecuted mammalian neighbors, such as black bears, panthers, and red wolves. By the 1960s loggers had felled the last of the big trees, including bald cypresses, cottonwoods, and sugarberries. Endless fields of cotton and soybeans, no place for a wild bird to rear a family, replaced them.
Most famous (and mourned) of the plots of big trees was the ill-starred Singer Tract, west of the river, in Louisiana. James Tanner made pioneering studies of the ivory-billed woodpecker in this tract, even while the forest and the bird were disappearing. A current mystery is the comparative scarcity of rusty blackbirds in the improving woodlands. “They used to winter in very large numbers in bottomland forests,” says Audubon’s Greg Butcher. “Some surveys show a decline of 90 percent, to under a million birds, in the last 40 years. The decline seems to have coincided with the clearing of forests after World War II. But other blackbirds have done all right, so perhaps they outcompeted the rusties on farms.”
Changes in American agriculture are transforming the landscape. As soybean and cotton farmers move out, the big trees are fast reclaiming their former habitat in the lower valley’s hot, wet climate, where about a million acres have returned to forest. Many plots are already filled with birds.
In spring migrant birds funneling up the lower valley’s myriad tributaries and backwaters find rich assemblages of prey—gnats, caddis flies, mayflies. The main stem remains in its manmade straitjacket of levees, rushing toward the Gulf at four to six miles an hour, faster in floods. Near Vicksburg, where the riverbed lies between 30 feet above sea level and 70 feet below, the bottom layer of water loses momentum. But upper layers, compressed and buffeted through an endless series of tight S curves below Memphis, increase in turbulence. “The river tumbles over on itself, creating a kind of sandstorm on the bottom and scouring it out,” Paul Hartfield of the U.S. Fish and Wildlife Service in Mississippi told me. “In times of high flow, small organisms like minnows and invertebrates [food for birds] have to get out of its path. They retreat into backwaters and behind sandbars. Other organisms constantly move up and down the banks with the water to escape the turbulence.”
The North American river most closely identified with birds ends in the sterile blob at its mouth. But reaching seaward from Louisiana and Mississippi are outposts of life, the wetlands and barrier islands normally teeming with the flight calls of birds John James Audubon himself knew. Now this region is in disarray, struggling to dig out from under the effects of one of the most appalling disasters in this country’s history.
In earlier times the river carried life-giving sediments in its rambling flow, filtering them out to build the delta below New Orleans and replenishing the marshes, which became nurseries for the Gulf’s marine life and vital habitat for its birds. Now levees and diversions cut off the Mississippi from the marshes and bottomland forests. Instead the levees speed it directly to the Gulf, bearing the stew of contaminants, pollutants, and agricultural nutrients that have leaked from cities and farms to the north.
The isolated river leaves behind a windrow of degraded wetlands along the shores of Mississippi and Louisiana. The reduced flow of fresh water spreading over the delta has created a vacuum, enabling salt water to enter marshes and cypress swamps, which become less attractive, even useless, to many species of ducks and other wildlife. Navigation channels and canals dredged for oil and gas extraction further ease the entry of seawater. Human mismanagement primed this region for disaster.
Katrina’s full toll on birds will never be known, remaining as deep a mystery as the fate of birds after all massive storms, year after year, which suck injured and exhausted migrants into the sea. Many survive being blown widely off course. In the days following Katrina, birders far inland in the area of Pickwick Lake on the Mississippi–Tennessee border were broadcasting reports of displaced individuals: a band-rumped storm petrel, a long-tailed jaeger, a black skimmer, a magnificent frigatebird, and a south polar skua. Far upriver, in Tennessee, a royal tern was feeding a young bird.
Barrier islands along the Gulf Coast are no stranger to ruin. Absorbing the sea’s impact, these offshore punching bags slow the killer waves and block the intrusion of salt water into mainland marshes. Grand Isle, along the southern border of the Mississippi’s delta, has been the only barrier island supporting homes and businesses. Like the others, it took a ferocious pounding from Katrina. The storm smashed houses and boats and, in the words of one observer, “rolled up the marshes like rugs.” A triumphant survivor was Grand Isle’s forest of live oaks and hackberries, forged in generations of storms and now a legendary refuge in spring and fall for migrant birds. Still, no one can guess the long-term effects on the island’s marshes and beaches.
The Chandeleur Islands, which comprise the Breton Island National Wildlife Refuge, form a long, arching shield east of the delta, and they may have taken a knockout blow. The surge swept away the historic lighthouse and much of the sand. Tommy Michot, a biologist who has studied these islands by land and air over a 20-year span for the U.S. Geological Survey, describes the impact left by the recent intensification of severe storms. “When monitoring, we used to ride a bike over the sand and shallow water between the islands,” he remembers. “In 1956 the Chandeleurs totaled more than 18 square miles. By 2002 they were half that, and after Katrina, it’s just two square miles. Some islands are subaqueous—just a few shoals.”
The Chandeleur Islands support what may be one of the greatest concentrations of sandwich terns in the world. Breton Island, the southernmost in the chain, was home to 4,500 nesting pairs of terns and, in 2005, perhaps 2,000 pairs of brown pelicans. But last June a tropical storm had already blasted the pelican colony, pushing oil from a nearby spill over it and killing 724 juvenile birds. While adult brown pelicans will surely visit, nesting on the island is doubtful for at least the next three to five years.
Big Branch Marsh National Wildlife Refuge, north of Lake Ponchartrain, likewise felt the pain of Katrina. Of primary concern was the hit to its pine forests, where as much as 70 percent of the “cavity trees” for southeast Louisiana’s largest colony of endangered red-cockaded woodpeckers snapped in hurricane winds. “We still can’t get into some areas,” says James Harris, a USGS biologist. “A lot of the pines jackknifed, but near the marsh the storm surge pushed downed trees into piles. We don’t have any figures, but we’re just not seeing the number of woodpeckers that’s normal here. Maybe a lot of them went looking for new foraging areas, but we’re confident that some were killed.”
Sabine National Wildlife Refuge, in southwestern Louisiana, stands out in its disrepair, even among other sections of the coast. Hurricane Rita, Katrina’s ugly successor, was the instrument of destruction here. Like several nearby refuges, Sabine suffered from saltwater intrusion of its fields and marshes, significantly diminishing waterfowl populations this past winter. “We have a huge debris field, six miles long, half an acre wide, and 6 to 10 feet high,” reports Donald Voros, leader of the southwest regional refuge complex. “We burned off a lot of oil that leaked from busted tanks that drifted in from who knows where. But it may take years to get rid of the toxic chemicals.”
Voros thinks the majority of wading birds and waterfowl survived, but he worries about other marsh inhabitants. “What concerns me most is the secretive birds, the ones that stay low in the grasses,” he says. “We had healthy numbers of rails. Sora, clapper, black rails—we had all of them. Now they could be wrapped up in the debris.”
Obscured by the immeasurable human tragedy in New Orleans itself is the flood’s impact on birds. In the past the city’s pockets of greenery were havens for weakened migrants. Now the familiar magnolias are gone from flooded neighborhoods, and thousands of shrubs have succumbed in ruined parks and home gardens. It may be harder to return music to the parks than to Basin Street.
But beyond the immediate cleanup and cries for better management remains the stark fact of the destruction left by Katrina. “The marshes that got hit aren’t coming back anytime soon,” insists Mark Davis, executive director of the nonprofit Coalition to Restore Coastal Louisiana, which is working to establish a balance between substantial hurricane and storm protection and a healthy and sustainable ecosystem. “The recovery of our pine forests is critical for migrant birds. Nobody knows the future, but if you just give up, there’s not going to be a future.”
As a consensus matured over recent decades that the Mississippi’s ills form a continuum from its source to the Gulf, individuals, government organizations, and 33 nonprofit groups, including Audubon, the Mississippi River Basin Alliance, Ducks Unlimited, and the Nature Conservancy (see “What You Can Do”), concerned with the river’s future have come together to find solutions to the mass of problems. They are pushing for policies that improve water quality, restore floodplain forests and wetlands, and manage the river to mimic its once natural alternation of high and low stages in season. The message now is clear: There ought to be more to the river than using it to float barges and drain human wastes.
A high priority in the upper valley is congressional legislation aimed at improving agricultural practices. A number of programs available through the federal farm bill, including the Conservation Reserve Program and the Wetlands Reserve Program, enable farmers and other landowners to upgrade the quality of their land while creating vital habitat for birds and other wildlife. Government scientists and environmental organizations are helping farmers make use of such programs, as well as reducing nutrient and chemical runoff to the river. (For more information on these farm bill programs, see “Green Acres,” Audubon, November-December 2005.)
Research in the Upper Mississippi is attempting to unravel the distribution and population trends for individual bird species. An example is Jon Stravers’s two decades of work with red-shouldered hawks, which has shown, for instance, that the raptors serve as a sort of “umbrella species”—where they thrive, other kinds of birds thrive, too. Stravers has found that a pair of prothonotary warblers and a pair of pileated woodpeckers are present in 100 percent of the red-shouldered hawks’ nesting sites. “Consequently,” he says, “we’ve been able to convince Corps biologists and state agencies to change their forest management policies in areas where red-shoulders are nesting—to manage forests for a mix of trees and water that the birds seem to prefer.”
As the river frees itself in the lower valley, destruction and fragmentation of the floodplain and its bottomland hardwood forests present similar problems for birds. A model for cooperation among government and nonprofit agencies has appeared in the joint ventures organized in several regions throughout the United States, primarily for waterfowl management. Participants in the Lower Mississippi Valley Joint Venture took the idea a step further by including all species.
Armed with detailed maps, U.S. Fish and Wildlife and USGS researchers have recorded the extreme fragmentation of lands adjoining the river, noting that small, isolated plots invite raccoons, crows, and cats, as well as cowbirds (efficient nest parasites), to prey on vulnerable forest songbirds. One solution has been filling in the gaps by obtaining easements or other agreements from cooperating landowners attracted by the Wetlands Reserve Program or other subsidies.
“We want to see where birds are going,” says USGS biologist Dan Twedt. “If we don’t like where they are going, can we do something about it? In other words, the plan is to fashion the returning forests to the birds’ liking.” Certain monocultures of pines, for instance, don’t supply foraging or nesting birds with the resources they need. New plantations can be strategically placed, with a mix of vegetation that provides optimal conditions. The aim is to determine the minimum size of a forest needed to sustain, let’s say, 500 pairs of a certain species. Proof of success will come when these forests attract a variety of birds, year after year, displaying high rates of reproduction.
The lower valley doesn’t include the acreage in public ownership that marks the Mississippi to the north. Where the landscape was once fragmented by owners of large holdings chopping it up, now ownership itself is fragmented. There is a scarcity of funds for land purchases. So government and conservation groups are forging links with the private sector along the river.
A shining example in Mississippi is Tara Wildlife, a 17,000-acre forest and resort that’s checkered with small ponds and shallow pits where, in season, visitors can see hundreds, sometimes thousands, of wading birds, as well as owls and songbirds in the forests, earning it a designation as one of Audubon’s 86 Important Bird Areas along the river.
Biologists are coming to grips with the damage from last summer’s hurricanes, but they say the long-term protections for birds—like people in the Gulf’s hurricane-prone regions—will depend on policies that view the river in its entirety.
Landmark legislation from decades past offers reason for hope. The banning of DDT and the passage of the Clean Water Act gave a significant lift to rebuilding the diversity of birdlife coursing through the Upper Mississippi and its tributaries. In 1970 there was only a single nesting pair of bald eagles on the upper river. Now 127 pairs nest in the region, and thousands more may be seen in winter. Neotropical migrants such as American redstarts, warbling vireos, and great-crested flycatchers are abundant in the Upper Mississippi River National Wildlife and Fish Refuge, which covers about 230,000 acres in four districts along 260 miles of the river.
Biologists and engineers have the knowledge and techniques right now to rebuild marshes over time by diverting water and sediment from the river. “But will this engineering also create habitat for birds?” asks David Muth, chief of planning and resource stewardship at Jean Lafitte National Historic Park and Preserve in New Orleans. “We can no longer afford to waste the river’s sediment load in order to maintain expensive ship channels. The channels have to be reengineered to get ships out of the Gulf and into the river by other means, and this will be very expensive.” The administration in Washington made a lot of promises right after Katrina, but, as people in New Orleans have pointed out, we spend more on wetland restoration in Iraq than we have been willing to spare for marshes in Louisiana. And that’s bad for both birds and people.
The Mississippi once defined the romance of a young nation pushing westward. It was the river of John James Audubon, of Mark Twain and his steamboat pilots, and of the colorful “showboat” gamblers who became the stuff of novels and movies. Today the true links to that swept-away time are Audubon’s birds—symbols of a once-wild river, enduring indicators of our heartland’s well-being.