But today one little canary-size honeycreeper is staging a startling comeback. Scientists recently discovered that the population of the native Hawaii amakihi has surged in low-elevation forests. After reports of sightings of the greenish-yellow birds spread, researchers from the U.S. Geological Survey (USGS) decided to take a look at low-elevation areas for the first time in about a decade. "There were amakihi flying all over the place," recalls Carter Atkinson, a USGS parasitologist. At more than half of the locations where few amakihi could be found 10 years ago, there were now thriving populations. "It really surprised us," Atkinson says. The amakihi population had virtually disappeared at low elevations by 1994; today scientists believe the species has rebounded to an estimated two birds per acremaking them the area's second-most abundant species, following the introduced Japanese white-eye.
Studies on banded amakihi indicate that the birds may be evolving a genetic resistance to avian malaria, something Charles van Riper, an ornithologist at the University of Arizona, first suggested in the late 1980s. In a controlled study that compared the physiological features of birds living at different elevations, birds from higher tiers injected with malaria had a 40 percent survival rate, whereas the amakihi found at sea level had an 83 percent survival rate.
The extreme isolation of the islands of Hawaii has produced many genetic anomalies, including mint that has no smell, raspberry bushes without thorns, and native bird populations without resistance to avian malaria. After visiting sailors unwittingly introduced mosquitoes in the early 19th century, the one-two punch of avian pox and malaria nearly exterminated Hawaii's birds. Some of them retreated to higher elevations5,000 to 6,000 feetwhere there are no mosquitoes and where the malaria parasite is unable to complete its breeding cycle. Still, Hawaii has more endangered forest birds than any other state. Of the 71 endemic bird species that remained in Hawaii at the end of the 18th century, 23 are now extinct, and 30 are so endangered that some populations have fewer than 50 individuals left on the islands.
The different climates of the various elevations scientists are exploring may provide important models to predict the effects of global warming on the transmission of disease. Atkinson believes, for instance, that a quick onset of global warmingor even a temperature increase of just one or two degreescould drive mosquitoes into the higher elevations. "It would be the final stroke for Hawaii's birds," he says.
At the very least, there is fresh hope for Hawaii's amakihi population, and evidence is mounting that even the most susceptible populations may be able to adapt. "I really believe that if we can figure out how the amakihi are coexisting with avian malaria," says Bethany Woodworth, a bird ecologist with the USGS, "it will give us really important clues that we can use to potentially save other Hawaiian species."
You might want to think twice before liberating your pet goldfish in the local pond. Recent studies suggest that the release of aquarium fish into U.S. waterways is altering ecosystems and displacingeven eliminatingnative species.
Until now, discharged ballast from ocean freighters had been thought to be responsible for introducing most of the nonnative species found in American waters. But earlier this year Brice Semmens, a biologist at the University of Washington, discovered otherwise. Semmens studied the presence of 16 species of Indian Ocean and Pacific fish on Florida reefs and compared the results with 10 years of diver reports, tropical fish trade data, and shipping-industry records. He found that these 16 fish were among the most popular imported aquarium breeds and that they came from waters not heavily traveled by Florida-bound freighters. While aquarium releases weren't witnessed, "we did the best you can do at pinpointing the source," notes Semmens. "[The study] makes a compelling case."
Today the National Oceanic and Atmospheric Administration (NOAA) has documented nearly 60 aquarium species in U.S. waterways. Scientists believe many have established breeding populations, including oriental weatherfish in Washington streams, oscars in Florida canals, and goldfish everywhere in between. One thriving species is the red lionfish. Native to Indonesia, Malaysia, and Australia, the lionfish has spread along the Atlantic coast during the past decade, from Florida to New York. In August NOAA biologist Paula Whitfield conducted research dives along a 90-mile stretch of North Carolina and found lionfish of every age, size, and number in 19 of 22 locations. All were feasting on small native fish. "Even in lousy habitat, we came across them," says Whitfield.
Whitfield and other scientists say that most aquarium fish are probably introduced by owners who can't or don't want to keep them. Unable to euthanize, give away, or otherwise get rid of the fish, the owners release their pets in lakes, bays, and other waterways. In an effort to halt aquarium releases, a national public awareness campaign was launched this fall, sponsored by government agencies and the Pet Industry Joint Advisory Council. The campaign aims to educate aquarium owners to the dangers of releasing fish by placing brochures in aquarium retail sites, stickers on tanks, and notices on fish-transport bags. The campaign also suggests alternatives to releasing fish, including donating them to nursing homes, hospitals, and zoos. Which is really the only humane way to release unwanted fishfor them and the environment.
Perched at 10,000 feet atop Colorado's Mount Werner, the Storm Peak Laboratory in Steamboat Springs offers front-row seats to a meteorological reality show of sorts. "When winter storms come through, we actually watch what happens in the cloud," says Randy Borys, an atmospheric scientist and director of the laboratory. What the lab's scientists learned recently is that air pollution is changing the physical composition of clouds and stopping snow from developing. This phenomenon, say Borys and a team of researchers from the Desert Research Institute in Nevada, may be contributing to the most severe drought the West has endured in the past 80 years.
In one study, Borys and his colleagues compared the amount of snow produced by clouds on a clean-air and a dirty-air day, and found that clouds laden with pollution produced 50 percent less snow. After combining that with past measurements, Borys estimates that in any given winter there is now a 15 percent to 25 percent reduction in snowfall as a result of emissions from cars, oil refineries, power plants, and other polluting sources.
Less snow spells big trouble for the West because "snowfall is the most important water source for the western United States," says Borys. Nevada, for example, depends on snowmelt for much of its water, and the Colorado River, which supplies water to most major population areas in the Southwest, is fed primarily by runoff from snowmelt.
Here's how the burning of fossil fuels inhibits the formation of snow: In a normal cloud, droplets form on particles like salt or dust in the atmosphere. "To get rain [or snow] you have to have coalescence of cloud droplets," says Doug Lowenthal, an atmospheric scientist at the Desert Research Institute. In other words, snow forms when cloud droplets bump into and adhere to ice crystals. As the ice crystals become heavier, they eventually break through the cloud and cascade to the earth.
However, as air pollution increases, the size of cloud droplets decreases, because in dirty clouds the pollution particles are so tiny that the resulting cloud droplets are too small to adhere to ice crystals. Thus, coalescence is inhibited, and the chance of a snow crystal becoming big enough to escape a polluted cloud is unlikely.
"We can't change global weather patterns," Borys says. But the findings at Storm Peak laboratory and other institutions make it clear that manmade pollution intensifies these effects. And that, Borys adds, is something "we can change."
In 1921, when Warren Harding was President and Babe Ruth was playing his second year with the New York Yankees, Audubon members visited the school of eight-year-old Jean Wattley, in Anderson, South Carolina. For five cents she received a pin and a one-year Junior Audubon membership. Wattley, now 91, has been active in Audubon for the past 83 years.
"Audubon would come into our school each year and talk to us about birds," recalls Wattley, who belongs to the Charleston Natural History Audubon Society. "They got us interested and taught us how to enjoy birds without harming them." The visit prompted her to become a passionate birder, and she has since pursued her hobby all over the world, including Antarctica. Even at her advanced age, Wattley's passion has hardly diminished; last winter she made an expedition to the headwaters of the Amazon.
After moving to Chicago in 1935, Wattley volunteered at the Chicago Academy of Sciences and was an active member of the Field Museum of Natural History. At the museum she befriended fellow birders, including the academy's director, William Beecher, with whom she traveled to the Galapágos Islands in the 1970s, and Roger Tory Peterson of field guide fame (who also served as Audubon's art director). Wattley assisted Peterson with book signings when he was in Chicago and worked to save a nature reserve in the city's Lincoln Park from becoming an extension of a golf course.
In 1979 she returned to her native South Carolina and has since nurtured a sanctuary on the grounds of her retirement community. Despite flagging eyesight, Wattley continues to spend two hours each morning filling more than 20 different bird feeders in her backyard. "If the peanut butter isn't out there first thing in the morning, [the birds] are out calling and letting me know," Wattley says. In recent years, however, wetlands near her home have been filled in and replaced by an industrial park and a shopping mall. "We used to have hundreds of chimney swifts and nighthawks that we just don't see anymore," she laments. "They cut down all the trees around me and built a 16-screen theater. I just don't hear the birds singing anymore. I could cry. It used to be a musical chorus."
Still, the indomitable nonagenarian hasn't given up hope. "Everywhere I go I speak to people, especially kids, and try to get them interested in birds," says Wattley, who recently gave a talk at the nearby Francis Beidler Forest Audubon Center. "A lot of people don't like to fool with eight- and nine-year-olds, butand I'm a prime examplethat's the time to really get their attention."
© 2004 National Audubon Society
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