While the concept of four primary North American migratory bird flyways is taken for granted today, it didn’t always exist. To understand the concept’s importance, one need look no further than the dramatic saga of the whooping crane.
In 1941, the whooping crane was reduced to 15 individuals. Demand for feathers by the ladies’ hat industry and agricultural drainage of nesting grounds had taken such a toll on North America’s tallest bird that Aldo Leopold wrote it off as a goner. Fortunately, recovery efforts have fostered a steady turnaround.
The fact that the majestic whooping crane did not follow the passenger pigeon into extinction owes to developments that preceded recovery efforts. Bird banding, for one, helped produce a better understanding of migration that led to improved management strategies.
Bird banding is traceable to Ancient Rome. Modern records, however, credit naturalist John James Audubon with conducting the first banding study in North America when, in 1803, he attached silver wires to the legs of a brood of phoebes and noted the return of two the following year. While observers had long been aware of waterfowl migrations, leg banding in the 1900s hastened the rate at which science made practical use of the information, eventually spawning the flyway concept.
Ornithologist Frederick Lincoln spearheaded bird migration studies for the U.S. Fish and Wildlife Service’s predecessor, the Bureau of Biological Survey.
“Recovery of banded ducks and geese accumulated so rapidly,” Lincoln wrote, “that by 1930 it was possible to map out the four waterfowl flyways’ great geographical regions, each with breeding and wintering grounds connected by a complicated series of migration routes.”
Until then, most federal lands set aside for natural resources, including those within the National Wildlife Refuge System, had been established as independent oases. Lincoln helped oversee an era of managing these lands so that important habitat would be available to waterfowl throughout their arduous journeys.
“When refuges were finally managed along flyways in the 1930s, they began functioning as a system; the parts became greater than the whole,” says Service historian Mark Madison.
Lincoln went further, raising the science of collecting bird data to a new level, literally. As an aviator and a biologist, Lincoln knew the advantage that flight would bestow in tracking waterfowl populations, even if his predecessors had been unconvinced.
“Before Lincoln, the agency just didn’t have much faith in combining biology with aviation,” says Madison. “The idea of making like the birds in order to study them seemed like an extravagance.”
But the pilot–biologist idea ultimately did take off, so to speak, and the aerial survey program has been instrumental in waterfowl management ever since.
Every year, pilot–biologists mimic bird migrations in the Atlantic, Pacific, Central and Mississippi Flyways. They’re responsible for most waterfowl banding on the continent. And they conduct aerial surveys with increasingly advanced technology, such as cutting–edge navigational equipment and computers that capture survey data with latitudinal and longitudinal precision.
The aerial survey program has advanced considerably since whooping cranes were first spotted wintering at Texas’s Aransas National Wildlife Refuge in 1941, 13 years before their nesting grounds were discovered at Wood Buffalo National Park in Canada.
“The aerial survey program has been invaluable to whooping crane conservation,” says Service endangered species recovery coordinator Wendy Brown. “The program has been critical in monitoring nesting and wintering grounds and the migration route of the remaining birds so that these areas could be protected … for them and, thankfully, for their descendants.”
Certainly, the whooping cranes’ future looks less daunting than it did 70 years ago. With two primary wild populations totaling about 430 birds and another 160 in captivity as of last fall, the species now numbers almost 600.
It’s hard to imagine such progress if the flyway concept hadn’t evolved as it has.
Ben Ikenson is a New Mexico–based freelance writer.
