What Do Birds Do for Us?
Some might not realize the tangible value of birds, but it would be foolish to underestimate how tough life would be without them.
Betts says the program is too new to offer up much data. And he's quick to stress that birds alone can't tell scientists everything they need to know about ecosystem health. "There haven't been very many rigorous tests--we still need more information on whether birds are going to well represent other components of biodiversity," he says. "But that said, if there are major problems, we're going to pick it up with birds."
Pest control, public health, seed dispersal, ecotourism, environmental monitoring--these are some of the ways birds benefit humans. There are many others:
* After every harvest, California's rice farmers must get rid of a waste product called rice straw. Burning it is cheap, but it also pollutes and is therefore illegal. An alternative, tilling the straw into the soil, can be very expensive.
Fortunately, farmers can enlist help from wintering waterfowl that travel along the Pacific Flyway. By foraging for grain, weeds, and bugs in flooded rice fields, birds like mallards help decompose the straw. This could reduce the need for tillage, providing considerable savings to growers, concluded a 2000 study from the University of California-Davis. Farmers would be well advised, the report noted, to flood their fields and create wetlands for these avian wayfarers.
* Pollination is often the realm of bees, bugs, and butterflies. But more than 900 bird species worldwide pollinate, too, and their sophisticated sense of geography suits them well to the task. The durian munjit, a wild fruit that is collected and eaten in northern Borneo, relies exclusively on spiderhunters, members of the sunbird family. A passerine called the Canarian chiffchaff pollinates the Canary bell-flower, an ornamental plant with edible fruit that grows on Spain's Canary Islands. (It was cultivated in the royal garden of England's Hampton Court Palace as early as 1696.) And when the cold weather keeps insects away, China's winter-flowering loquat tree reproduces with the help of two passerines, the light-vented bulbul and the Japanese white-eye. The loquat's fruit is eaten in many forms and used medicinally.
Tinkering with the environment disrupts these relationships. Researchers have chronicled how the introduction of the Polynesian rat to Easter Island might have wiped out a parrot species that pollinated a palm. With the parrots extinct (and rats consuming the palm seeds), the most common trees in the island's subtropical forest died out around the 15th century. One hypothesis suggests that without palm wood to build fishing canoes, a culture advanced enough to carve the island's iconic stone statues fell into steep decline.
* Seabird guano--rich in nitrogen, phosphorus, and other nutrients--"provides an important source of fertilizer and income to many people living near seabird colonies," according to Utah's Sekercioglu. This has been true for centuries: Guano was considered essential to the Incas' agriculture, "upon which their civilization was based," wrote Edward Howe Forbush in 1922. Two years earlier ornithologist Robert Cushman Murphy declared that the best Peruvian guano was 33 times as effective as barnyard manure based on its nitrogen content.
"Unfortunately," Sekercioglu writes, guano production "is one of the most threatened of avian ecosystem services, due to the rapid decline of seabirds worldwide." Among the culprits are fishing longlines, which entrap birds such as black-browed albatrosses.
* Birds possess skills that historically made them useful to militaries. During World War I, pheasants detected oncoming hostile aircraft at long distances and "gave the alarm by their insistent cries," says one account; canaries, of course, sensed poison gas; gulls followed submarines in search of garbage. Carrier pigeons successfully navigated through shellfire (and past bullets aimed at them). They transported messages that helped the Allies capture German submarines, and that saved the crews of downed seaplanes and a sunken minesweeper. It turns out birds aren't just useful. They're bona fide heroes.
This story ran as "Follow the Money" in the March-April 2013 issue.