Worldwatch Paper #165: Winged Messengers: The Decline of Birds

Tailspinning Bird Populations Highlight Biodiversity Crisis

Washington, D.C.—Bird populations around the world are plummeting faster than ever before, and human factors—from population growth to habitat destruction and climate change—are at the center of this demise, reports a new study from the Worldwatch Institute, a Washington, D.C.-based research organization. Human-related factors are threatening 99 percent of the most imperiled bird species and contributing to what has become the greatest wave of extinctions since dinosaurs disappeared 65 million years ago, according to Howard Youth in Winged Messengers: The Decline of Birds.

“Declining bird populations mark not only the loss of unique species," says Youth, "but also the unraveling of delicate natural balances. Birds are valuable environmental indicators because they warn us of impending problems through their waning or flourishing populations.”

With twelve percent of the world’s bird population—almost 1,200 species—facing extinction in the next century, Winged Messengers outlines an array of phenomena that is accelerating this demise. These include:

  • Habitat loss: Deforestation rates from 50,000 to 170,000 square kilometers a year pose the single greatest overall threat, jeopardizing 85 percent of the world’s most threatened bird species. While forest re-growth initiatives offset the net losses, for many native animals and plants, simplified plantation monocultures are no substitute for more complex natural forests.

    Roads and power lines frequently cut through forests, fragmenting them, increasing the chance of fatal collisions, and providing pathways for predators, competitors, and exotic plants. Intensive hunting often follows when roads cut into forests.

  • Alien attacks: A rise in global trade and travel over the past century has led to an acceleration in the introduction of exotic (non-native) species. Exotic species—including snakes, rats, cats, plants, and insects—now menace a quarter of globally threatened bird species.

  • Chemical threats: Large oil spills threaten many seabird populations, but small, less-publicized daily tankers also kill birds. Terrestrial habitats also face threats from oil and natural gas exploration, and transport via pipelines. Worldwide, pesticides kill millions of birds on water and on land.

  • Hunting, Capture, and Fishing: Illegal hunting and poorly regulated laws lead to the killing of millions of birds around the world. Birds can be loved to death too: Almost a third of the world’s parrot species are threatened with extinction because of the pet trade, and long-term habitat loss. Longline fishing also claims hundreds of thousands of seabirds—23 species now face extinction—when they are inadvertently hooked on baited lines and drowned.

  • Climate change: Recent evidence of earlier bird migration and nesting in some species seems to indicate early effects of global warming. Scientists fear that in coming years climate change will alter vital bird habitats, from tundra to subtropical coastlines, even pushing some localized species towards extinction.

Efforts by governments and private organizations to reintroduce bird species paint a bright future for some jeopardized species, but careful wildlife management can go awry, says Youth. Habitat restoration can be complicated when tree or shrub species have vanished, soil is compacted, water tables have dropped, or chemicals have poisoned an area. Costly projects may yield only marginal results, not fully compensating wildlife for habitats lost.

And while restoration efforts are important in some areas, the best way to preserve biodiversity, says Youth, is to not let species and their complex habitats become endangered in the first place. “While we need protective legislation in some areas, often just the full implementation and enforcement of already established international laws and agreements would go a long way toward saving the world's remaining bird diversity.”

Youth says that new alliances are proving fruitful in documenting existing species and preventing further species losses.

Conservation biology—a new approach to natural habitat protection that blends biology, conservation science, economics, and the mutual engagement of conservationists, communities, and business—has changed the focus of biodiversity protection. This new approach factors in not only protected areas for conservation, but also adjacent lands, water resources, and the people who inhabit and use them.

Biodiversity protection can be combined with money-making ventures, bringing enterprise and environmentalism together. Shade-grown coffee is one such initiative. Growing coffee in the traditional way beneath a tropical forest canopy protects natural habitats, providing shelter to resident and migratory birds and using fewer chemicals than those grown on pesticide-heavy “sun coffee” farms. Organic farms and those using integrated pest management also provide more diverse food sources and safer habitats for birds.

Scientists are also tapping into one of the world’s fastest growing outdoor hobbies, bird-watching, as a means for heightening conservation efforts. Growing ranks of birders are providing a powerful infusion of eyes and ears that assist scientists in monitoring bird populations and mapping out the world's most important remaining bird habitats.

“The actions needed to ensure a secure future for birds are the very same ones needed to achieve a sustainable human future,” says Youth. “Wildlife conservation must be worked into and be compatible with rural, suburban, and urban planning efforts that improve the prospects of the world’s poor while making our cities and industries safer for all living beings.”

“Birds provide us with food, inspiration, a link to nature, and an alert system for detecting environmental ills, but today, this feathered resource is in great need of human attention.”