• Flight Today

The Beaver and the Swans

How de Havilland's famous bushplane has helped protect a species.

• By James Wynbrandt
• Air & Space Magazine, July 01, 2006

“Pair at two o’clock.”

Flying at 500 feet, pilot and biologist Bruce Conant looked in the direction I called and banked the

de Havilland Beaver toward the swans on the lake a mile away. We were flying as part of a month-long U.S. Fish and Wildlife Service project to study the Alaskan population of trumpeter swans before their annual migration south. Throughout last August, 14 aircraft flying up to eight hours a day would scour some 50,000 square miles of habitat, the largest attempt in the world, project managers believe, at an exact census of wildlife. Our job was to record the location of each sighting and tabulate the number of adults and young in every brood. With wildlife survey flight time in my logbook, I was on board as a volunteer observer.

A flyby of the swans on the lake yielded no sight of the young, called cygnets, whose tell-tale gray makes them hard to see from a distance. Using a knitting needle as a stylus, I input the pair of swans’ position on the touch-screen map, a digitized, GPS-linked version of U.S. Geological Survey maps we used to navigate and to record sightings. From the tabulation subscreen that appeared, I selected a “P” (for “pair”) and confirmed the entry. Had there been cygnets, I would have input their number.

We were flying into the Susitna Valley. On three sides of the lake, peaks of the Alaska Range rose, squeezing the northern end of the valley into nothingness, but Conant is a veteran of tight spots. After 30-plus years of bush flying, not much rattles him.

We were hoping for cygnets. Earlier discussions among observers had come to the dispiriting conclusion that many of the fledglings were undergrown, and probably wouldn’t be strong enough for the flight south. “You wonder what goes through the minds of those swans,” Conant said. “They must know the cygnets aren’t going to make it. I guess they don’t give up until the very end.”

Named for its call, the trumpeter swan, Cygnus buccinator, is one of the world’s largest flying birds, with weights up to 35 pounds and wingspans reaching eight feet. Once hunted for food and feather, by the turn of the last century they were thought extinct, victims of the slaughter of species that led to federal regulations to protect the nation’s wildlife. The Fish and Wildlife Service has monitored swan populations since the 1930s, when several dozen trumpeter swans were discovered in Yellowstone Park. In 1954 a population in the hundreds was found in southern Alaska.

Their size, magnificence, and brush with extinction have made trumpeters avian celebrities, and in addition to the protection of law, they enjoy the support of an organized advocacy group, the Trumpeter Swan Society. The society supports research into the sources of the lead that has poisoned thousands of the swans in the Northwest in recent years and pays close attention to the results of the aerial census, conducted every five years.

The swans’ anti-camo plumage is a great help to the census-takers. Occasionally a flash of brilliant white will warrant a closer look, usually to reveal itself as a bit of wind-whipped lake foam, sunlight reflecting off a rock, even a sun-bleached moose rack. But for the most part the adult swans are unmistakable and hard to miss, whether on a cobalt-blue alpine lake or nesting in the green reeds encircling a glacial pond.

The survey is alternately exhilarating and monotonous. In high-density areas, where it seems every one of the endless lakes has at least a pair, the project has the feel of a cattle roundup, as we cut and wheel one way, then another. But in some USGS quadrants, the terrain in the 15-mile square is unchanging and devoid of trumpeters, and an hour or two without a swan is enervating and mildly depressing, no matter how magnificent the scenery.

Fish and Wildlife Service crews and aircraft typically operate in remote areas, and sometimes eddying rivers, small lakes, or unimproved strips are their only airports. In this roadless environment, the air crews have adapted strategies ranging from packing extensive survival gear aboard to modifying both airframe and powerplant. The queen of the modified fleet is N754, the one-of-a-kind de Havilland DH2 Beaver that Conant flies.

N754 was modified in 1976, when Jerry Lawhorn, then the aviation manager of the Fish and Wildlife Service’s Alaska region office, worked with Volpar Inc. of Van Nuys, California, to customize the aircraft for aerial surveys. On one of the many days last August when we couldn’t fly because of low ceilings, Conant and I dropped in on Lawhorn at his home in Anchorage. A picture of N754 hung on the wall opposite the front door. In the living room, Lawhorn joked about the oxygen canister he had to carry around, referring to his “range between refueling.” Settling into a couch below a pair of bighorn sheep trophies, Lawhorn recalled spending hours riding along with survey pilots and watching how they operate so that he could explain to Volpar exactly what he needed for counting critters from the air. Lawhorn was no stranger to aircraft design. A pioneer in bush operations, he had designed and built his own airplane shortly after arriving in Alaska in the late 1940s.

For wildlife surveys, Lawhorn needed an aircraft that was simple to operate and had superb forward visibility. Most turbine-powered Beavers use a Pratt & Whitney PT-6 engine, but that engine’s exhaust stacks, exiting from the side, interfere with an observer’s view. Volpar had been converting Grumman Gooses from piston engines to 715-shaft-horsepower Garrett 331-2UA-203D turbines. Hoping for a military contract to do the same for de Havilland Beavers, the company was happy to work with Lawhorn to make a single example of what it hoped to produce in large numbers. Lawhorn was interested in the Garrett engine because its exhaust exits from the bottom and doesn’t interfere with the pilot’s visibility. That engine is what gives N754 its distinctive needle-nose nacelle. Except for narrow frame posts, the windshield provides unobstructed front-to-side observing. And on the instrument panel, switches, power levers, and handles have been repositioned for simplicity of operation.

“It had to be biologist-proof,” Lawhorn

said. Every Fish and Wildlife Service pilot-biologist has a baccalaureate in biological sciences, a minimum of 500 hours of flight time, and an instrument rating. Beyond that, some come with more experience in biology than in aviation.

An aircraft that has been as highly modified as N754—different engine, panel layout, and avionics from those aircraft holding the Beaver’s type certificate—would ordinarily have to go through a series of certification tests to win approval from the Federal Aviation Administration. But the airplanes that fly the aerial surveys come under the purview of the Department of the Interior, and they fly with waivers from the department’s Office of Aircraft Services.

No survey airplanes were flying near Fairbanks in mid-August. Crews had been grounded by smoke from forest fires. When rain had finally cleared the smoke from the state’s interior and crews were airborne again, I went surveying with Karen Bollinger in a Cessna C-206 near the confluence of the Tanana and Yukon Rivers, some 100 nautical miles west of Fairbanks. It was here that one of the first references to Alaska’s trumpeters was recorded: In 1870, a traveler noted the greased locks of the Tanana Indians “powdered with swan’s down, cut up finely…presenting a most remarkable and singular appearance.”

Even then trumpeters were scarce, which makes the resurgence witnessed from the air over the last three decades remarkable, according to the biologists in the Fish and Wildlife Service. The first aerial survey, conducted in 1975, counted 4,170 trumpeters. By the 2000 census, the total reached 17,155.

Brood size is the key to the swans’ future, so an accurate tabulation of the young is important. Their tendency to huddle together makes the cygnets hard to count from 500 feet. Over one such brood, Bollinger pulled the power, extended flaps, and made a dive-bombing turn for a closer look. The swans seemed not to notice the airplane. Sometimes multiple passes are required. (Observers are judged largely on their ability to endure these gut-wrenching maneuvers without puking.) I was lucky; on our first pass I could clearly see four cygnets following their parents into the water.

By the end of August, N754 was operating out of Bettles, north of the Arctic Circle, along with a C-206 that carried bio-pilot Jack Hodges and observer Debbie Groves. The census was in an accelerated dash to the finish. Groves would soon begin to tabulate the data.

Once the database is complete, it will provide information for land use planning and policy decisions. Placement of power lines, establishing boundaries of wildlife refuges, issuing permits for mining operations—all have been influenced by the results of previous surveys.

This year’s final count was higher than expected: 24,105. But for all the concern about the trumpeters’ future, it’s the census and the Alaska region’s unique aircraft and operations that seem most endangered. At $229,000, the survey’s cost about equalled the region’s 25 annual counts of other wildlife combined. The Fish and Wildlife Service tracks other migratory birds as well as sea otters, moose, and bears. “I think it’s really questionable whether it will ever be done again,” said Russ Oates, a biologist and Fish and Wildlife manager in Alaska. “There’s been a lot of skepticism about putting this much money into a species that has obviously recovered from its all-time lows.”

Oates believes that monitoring the swan populations is still necessary. “We don’t want this species to decline again,” he said, adding that 24,000 Alaskan trumpeters plus the few thousand elsewhere are relatively small numbers for the worldwide population of any animal.

“I can tell you I’ll be here in 2010, and I’ll be putting in a proposal,” Oates said a moment later. Like the trumpeter swans, the census takers know a thing or two about fighting for survival.