Bees may be bouncing back from yearly declines, but experts remain concerned about their future.

Bees have hit it big on the national radar with their mysterious disappearing act known as CCD – colony collapse disorder – which is characterized by the sudden, complete absence of honeybees in a colony.  They simply vanish, with no trace of foul play and no bodies left behind.

In late 2006, about a quarter of participating beekeepers started reporting missing colonies.  And the number of apiaries reporting CCD climbed to 36 percent from 2007 to 2008.  But the 2008-2009 survey found that only a quarter of apiaries reported any evidence of CCD, and the latest yearly bee survey found that commercial beekeepers reported having lost fewer bees, due to all causes, this past winter than the winters before.

“The drop in losses is encouraging,” said Jeff Pettis, one of the survey authors and research leader of the Agricultural Research Service Bee Research Laboratory.  The survey – conducted by the Apiary Inspectors of America and the U.S. Department of Agriculture – checked on about 20 percent of the country’s 2.3 million colonies.

In 2007, beekeepers reported winter losses of 32 percent.  In 2008, they reported 36 percent.  This past year, winter losses have dropped to 29 percent.

“If the average loss is 20-25 percent, it’s sustainable to keep up a bee business,” said Dr. Eric Mussen, a honeybee expert at the University of California, Davis.  “If you’re much higher than that, you’ll have to have some other income source.”

Bees die in the winter for many reasons, including starvation, pests, and CCD.  In the 1970s, beekeepers expected 5-10 percent losses over the winter from starvation, diseases, or mismanagement.  In the 1980s, two different mite species decimated bee populations – cutting them in half.  The more aggressive mites essentially wiped out wild bees by the mid-1990s.

Honeybee populations have mostly stabilized from the mite attacks by the beginning of this decade, with beekeepers expecting losses of 20-25 percent every winter.  The mites are still prevalent, but bees seem to have learned to live with them, especially with the help of chemical treatments.

While the new statistics offer a glimmer of hope, the honeybee crisis is far from over. Scientists still have not identified the causes of CCD. However, the Agricultural Research Service has undertaken a five-year research program aimed at improving the health of honeybees. Researchers and beekeepers alike hold out hope that such efforts will pay off.

Silence of the Bees is the first in-depth look at the search to uncover what is killing the honeybee. The filmmakers of Bees take viewers around the world to the sites of fallen hives, to high-tech labs, where scientists race to uncover clues, and even deep inside honeybee colonies. Silence of the Bees is the story of a riveting, ongoing investigation to save honeybees from dying out. The film goes beyond the unsolved mystery to tell the story of the honeybee itself, its invaluable impact on our diets and takes a look at what’s at stake if honeybees disappear. Silence of the Bees explores the complex world of the honeybee in crisis and instills in viewers a sense of urgency to learn ways to help these extraordinary animals.

Silence of the Bees premiered on PBS October 28, 2007.

Exclusive Podcast: In this podcast, scientists and bee experts featured in the program discuss the crucial role that honeybees, a “keystone species,” play in our economy and ecosystems, as well as bees’ fascinating social organization and what we can do to reverse the decline of nature’s pollinators.

In the winter of 2006, a strange phenomenon fell upon honeybee hives across the country. Without a trace, millions of bees vanished from their hives, leaving billions of dollars of crops at risk and potentially threatening our food supply. The epidemic set researchers scrambling to discover why honeybees were dying in record numbers — and to stop the epidemic in its tracks before it spread further. Buy the DVD. This film premiered October 28, 2007.

The role honeybees play in our diet goes beyond honey production. These seemingly tireless creatures pollinate about one-third of crop species in the U.S. Honeybees pollinate about 100 flowering food crops including apples, nuts, broccoli, avocados, soybeans, asparagus, celery, squash and cucumbers, citrus fruit, peaches, kiwi, cherries, blueberries, cranberries, strawberries, cantaloupe, melons, as well as animal-feed crops, such as the clover that’s fed to dairy cows. Essentially all flowering plants need bees to survive.

A daunting question is: If honeybee colonies were so severely affected by CCD that pollination stopped, could we lose these crops from our markets and our diets forever?

Honeybees pollinate about 100 flowering crops.

“We’re not there yet,” says Jeff Pettis of the USDA. Pettis says there are steps researchers and beekeepers can take to ensure that the bee population doesn’t plummet to catastrophic levels. “One measure beekeepers have been taking is to keep bees as healthy as possible — improve nutrition and reduce stress,” says Pettis. Consumers have become more demanding and expect to have fruits and vegetables available to us all year round. In order to achieve this, commercial beekeepers haul colonies of honeybees across the country so their pollination services can serve all growing seasons. The season may start with almonds in California, then move on to apples in the Northwest, cranberries in New Jersey and Maine blueberries. The constant moving about places stress on the bees. In addition, certain crops that may be in the pollination circuit, like cranberries and cucumbers, are not very nutritious for bees. To keep the bees healthy, beekeepers may need to ease up on their schedules. It may be necessary for them to retire bees for a particular season or skip some less nutritious crops entirely.

Of course, nature has its own safeguards to keep crops pollinated. Honeybees aren’t our only pollinators. Other insects and birds pollinate fruits and vegetables as well. The problem with other natural pollinators picking up the bees’ slack is that today’s agricultural industry has simply grown too large for them to keep up. The leviathan that is U.S. agriculture creates a huge demand for pollination. Because honeybees are relatively mobile and can pollinate a generous number of crops, they have been the ideal recruits to meet our crop needs. But honeybees don’t perform such feats naturally without help — lots of it. Commercial beekeepers keep colonies nourished and healthy and move their hives from state to state in semis, selling their pollination services to farmers at a premium.

With the threat of CCD looming, researchers are starting to study how other pollinators like the larger bumble bees could step in for honeybees. “The Dutch have figured out how to use bumblebees,” says Pettis. Bumblebees share many similarities with honeybees. Both are social nesters, although the bumblebees’ society is not as highly ordered as that of honeybees. Also, bumblebees make a new nest each spring by solitary queens, who hibernate through the winter. Honeybees remain in the old nest.

Perhaps the biggest consideration is an economic one. Bumblebees last just 2 months and cost $200 per colony, whereas honeybees can last several months in the summer with colony rentals running only $100 to $140. As a result, the use of bumblebee pollination is usually confined to high-value crops like tomatoes. Clearly, the use of bumblebees is a step in the right direction, but not a final solution.

“There’s nothing waiting in the wings that can replace honeybees at this time,” says Pettis, “but we can solve the problem in honeybee health.” Pettis says that by focusing on reducing stress and improving nutrition, beekeepers can limit some of the factors that potentially lead to disastrous conditions like CCD, thereby keeping bees — and our diets — healthy.

Each January, the people of Kundha Kulam, a parched farm town in southern India, raise their eyes to the sky, searching for signs of life-giving rain. But they are not looking for clouds. They are watching instead for the birds that arrive on the vanguard winds of the oncoming monsoon. At the sight of the first flick of feather, the villagers breathe a sigh of relief, knowing that their crops will soon get a welcome drink.

This week, NATURE takes you from Kundha Kulam’s vibrant monsoon marshes to the rugged American Rockies to explore the worlds of Extraordinary Birds. Along the way, viewers meet a Scottish father and son who have taken up the ancient hunting art of falconry, a performer who works wonders with a pretty smart parrot, and some senior citizens who have developed strong attachments to some feathered friends. There are also homing pigeons that deliver film, rat-catching barn owls that protect farmers from pests, and hummingbirds that show their prowess as long-distance flyers.

In each case, NATURE’s Extraordinary Birds highlights the intimate links that people have forged with birds. In Kundha Kulam, for instance, “if the birds come, we know we will be prosperous,” says a resident. Like the robin that is the harbinger of spring, or the lonely honk of a migrating goose that signals the arrival of another winter, the herons, ducks, and pelicans that swarm to the flooded fields around Kundha Kulam have become a powerful symbol of the cycle of life.

In many instances, however, birds are more than just symbols — they are companions. In a convent in New York state, for example, Sister Barbara Seaward has founded the group Feathered Friends. She, along with others in her community, conduct pet therapy sessions for those in nursing and retirement homes. The residents agree that there is nothing quite like a visit from a cockateil or a cockatoo to lift the spirits.

And in the whitewater rafting canyons of Colorado, guides use homing pigeons to safely deliver a valuable commodity — photos of customers splashing their way down the rapids — back to home base, so the keepsakes are waiting when the rafters return from their adventure. The flying film couriers have become an essential business partner.

In eastern India, homing pigeons play a different role: they are law enforcers. Despite the introduction of radios and e-mail, the state police force of Orissa still keeps nearly 700 pigeon police available to shuttle messages between far-flung stations, according to British Broadcasting Corporation reports. But the century-old pigeon force may not last long into the millennium, as budget makers are convinced the birds are no longer needed.

In Florida, however, sugar cane farmers are eager to enlist the aid of birds. With help from University of Florida researcher Richard Raid, who is featured on NATURE’s Extraordinary Birds, the farmers have encouraged ghostly-white barn owls to nest near their fields. The birds perform a valuable pest control service, with each nesting pair capable of catching and eating almost 3,000 rats a year. They are “nature’s rat traps,” Raid says. Each year, the rodents cost sugar cane farmers nearly $30 million in crop damage.

Like other birds, however, the barn owl is a powerful symbol for many. “Many people in the [Caribbean] islands and Central and South America believe that it is bad luck to see a barn owl, particularly during the day,” says Raid. “Rumor has it that to see one forewarns the death of a friend or a relative in the very near future.”

Despite their scary reputation, however, the once common owls are becoming endangered in some areas and need some human help, such as the construction of nesting and roosting boxes. Raid and his colleagues are testing models of barn owl boxes mounted on posts to see how receptive the birds are to such homes. Sugar cane grower Wayne Boynton, who has earned the nickname “Godfather of Barn Owls,” says owls have moved into all the boxes he has put up on his 3,000-acre farm. “It’s like [the movie] Field of Dreams,” he says. “If you build it, they will come. It’s that simple.”

Echoing a sentiment heard elsewhere around the world about other birds, Boynton believes that “you can’t have too many barn owls.” They are, indeed, extraordinary allies.

Migrating animals are often welcomed and celebrated as a sign of seasonal change. Red-breasted robins herald the coming of spring, while the mournful honk of a goose heading south hints at the coming of winter. But there is one animal whose migrations cause fear: the locust.

As NATURE’s Earth Navigators shows, locusts look like grasshoppers and are in fact a close relative. But unlike grasshoppers, locusts undergo a remarkable change when their populations grow. At high population densities, locusts may change body shape and size, and then band together into huge, highly mobile swarms that set off in search of food. The changes are so dramatic that researchers once believed that swarming and non-swarming locust forms were different species.

For farmers, Farmers fear these swarming pests. In Africa, India, and Australia, swarms have eaten 20,000 tons of grain in a single day. And some swarms can do much more damage: the largest swarm ever recorded contained an estimated 12.5 trillion locusts. It covered several hundred square miles. Such swarms are so big that they are easily tracked by radar.

Locust swarms also once threatened farmers in the western United States. In one famous case in 1848, an enormous swarm of long-horned locusts descended on fields tended by new settlers near Salt Lake City, UT. But just when the farmers feared they would face starvation, flocks of gulls arrived, making a meal of the tasty insects. The settlers were so grateful to the bird, called the California Gull, that Utah eventually named it the state bird and erected a monument in its honor in a city square.

Today, farmers no longer rely on birds to keep locusts in check. They use everything from pesticides to germ warfare to kill the pests. And they even rely on sophisticated satellites to keep an eye out for the weather conditions that can promote swarming. Still, locusts remain a significant threat to farmers in many parts of the world. When they see the sky darken and hear the buzz of wings, they know a hungry menace is on the move.

Photo courtesy of the G. Eric and Edith Matson Photograph Collection at the
U.S. Library of Congress