Nearly a third of the wild birds in the United States and Canada have disappeared since 1970, an astonishing loss that suggests that the very fabric of North American ecosystems is falling apart.
The journal Science reported the disappearance of 2900 million birds in the last almost 50 years. This finding was the result of a large study conducted by a team of scientists from seven research institutions in the United States and Canada.
Even we, ornithologists and directors of two important research institutes that led this study, were surprised by the results. We knew of well-documented losses between shorebirds and songbirds. However, the magnitude of the losses in 300 bird species was much larger than we expected, in addition to extending alarmingly throughout the continent.
This study is particularly interesting due to the reliability of the data. Birds are the best studied group of wildlife; Scientists and citizens alike have carefully monitored their populations for decades. And, in recent years, scientists have been able to track the volume of night bird migrations through a network of 143 high-resolution meteorological radars. This study links all these data and the results indicate a crisis in development. More than half of our grassland birds have disappeared, 717 million in total. Forests have lost more than a billion birds.
Much of the losses have occurred among common species. The population of Sergeant Thrush has lost 92 million birds. A quarter of all tiles have disappeared, along with almost half of Baltimore's orioles. These are the birds we know and love, which are part of the birdlife that gives life, color and melody to North America every spring. Although it is still essential to save birds under a greater danger of extinction, the loss of abundance in our most common species represents a different and frankly more ominous crisis.
Birds are indicator species that serve as extremely accurate barometers of environmental health, and their massive decline indicates that the planet's biological systems are in trouble. Unfortunately, this study is only the most recent testimony of such a long line of evidence.
For example, a study conducted in Germany reported a mid-summer decline in flying insect biomass of 82 percent during the last quarter of a century. 40 percent of the world's amphibians are in danger of extinction, according to the International Union for the Conservation of Nature. Atlantic bluefin tuna stocks have declined to 3 percent of its historic population and Atlantic cod fishing in the United States reached low levels never seen before. A report from the United Nations warned this year that about one million species of animals and plants are in danger of extinction. That is "more than ever before in the history of mankind," according to the report.
All these statistics underline the dominant characteristic of the Anthropocene, the new geological era defined by the fact that the planet's natural systems are being deeply altered by human behavior. How far should these losses go for society to say "Enough!"?
We can and should do better, if only for our own interest, since, if the birds are in trouble, that also implies that we are in trouble.
The fate of the laity gives us an example. These yellow-breasted songbirds from the broad valleys of the United States depend on healthy grasslands that play an important role in the filtration of runoff water. But in the last half century, 73 million women from the east and 65 million women from the west have disappeared as grasslands have been lost and in many communities water has become contaminated with agricultural runoff.
Fortunately, not all news is bad. North American ducks and geese populations have grown 56 percent since 1970, according to the Science article, and it's no accident. During the first half of the twentieth century, hunters were greatly concerned about the decline in duck populations, as severe as the one we are witnessing among common songbirds today. The United States and Canada responded with laws to protect wetlands and collaborated with Mexico to safeguard waterbird migration. Conservation management was increasingly influenced by science. Private philanthropy, especially from Ducks Unlimited, generated significant financial support for the acquisition of wetlands. Federal and state governments restored and protected millions of additional hectares of wetlands. The result: today waterbird populations are booming.
This success in the management of water birds can point the way forward. We need bold conservation campaigns with a holistic approach throughout North America, comparable to those that achieved the recovery of the duck population. These efforts do not require the blocking of lands in fenced wildlife reserves. Conservation programs under federal agricultural law on private lands in the upper Midwest helped to increase duck populations, while providing flood protection and keeping the supply of drinking water safe. Expanding the scope of agricultural law conservation programs would produce more of these benefits. In addition, a bipartisan measure in the House of Representatives known as the U.S. Wildlife Recovery Act would allocate some $ 14 billion of the federal treasury to breathe new life into state and district wildlife habitat conservation programs. , which are usually poorly funded.
The loss of habitat has been the main cause of the decrease in the number of birds, and efforts to reduce the development of wild lands and suburban expansion should remain at the forefront of conservation priorities. In addition, we have to deal with other threats to bird life. Feral and domestic cats that roam outdoors cause great mortality among birds every year, as do collisions with buildings, communications towers and power lines. Recent evidence shows that pesticides, such as neonicotinoids, may be directly or indirectly responsible for the death of a large number of birds. It is also worrying that scientists are just beginning to assess the ravages of climate change in bird populations.
What we need most is a social change in the values we give to live in healthy and functioning natural systems. Natural habitats should not be seen as a dispensable luxury, but as a fundamental system that fosters human health and sustains all life on the planet. The loss of almost three billion birds signals a budding crisis that we have the power to stop. We ask all our legislators, political candidates and voters throughout the continent to give more value to the protection of our common home, the great melting pot of natural systems that we share with other species and that we must protect for future generations.
(John W. Fitzpatrick is director of the Cornell Ornithology Laboratory. Peter P. Marra is director of the Georgetown Environmental Initiative and previously directed the Smithsonian Institute Migratory Bird Center).
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