Vanishing Birds — Something To Be Alarmed About!
October 7, 2019 at 8:39 p.m.
By -
And flowers through the grass
Joyously sang,
While the tribes of birds sang.
Walther von der Vogelweide’s poem “Dream Song,” written almost 900 years ago extols the virtues of the wide variety of songbirds – birds that are one of earth’s treasures. It would be difficult imagining a world without them.
Rachel Carson, in her prophetic book “Silent Spring” in 1962, wrote about losing birds thusly: “On the mornings that had once throbbed with the chorus of robins, catbirds, jays, wrens, and scores of other bird voices, there was now no sound.”
Her concern was the widespread use of pesticides, and scientists this past month have documented that North America since the 1970s has lost nearly 3 billion birds, about 30 percent of the total. Pesticides are only partly to blame.
Findings raise fears that some familiar species could go the way of the passenger pigeon, a species once so abundant that its extinction in the early 1900s seemed unthinkable. I have written about passenger pigeons before noting that “in the 1800s and before, migratory flocks of passenger pigeons were so immense that they blanketed the skies of eastern North America. One individual recounted a mile wide swath passing overhead blocking the sun for three consecutive days. The birds flew at an estimated speed of about 60 miles an hour. Nesting birds took over entire forests, trees were crammed with dozens of nests, collectively weighing so much that branches would break and tree trunks would topple. Surface vegetation was destroyed by the thick layers of the bird's excrement. Sound was overwhelming. But the birds were not just noisy, they were tasty too, and their arrival guaranteed an abundance of free food.”
The greatest current losses have occurred to birds living along shorelines and in grasslands. They have declined by 53% since 1970, a loss of 700 million adults in the 31 species studied, including meadowlarks, and northern bobwhites. Shorebirds such as sanderlings and plovers are down by about one-third. Habitat loss may be partly to blame. Of the nearly 3 billion birds lost, 90 percent belong to 12 bird families, including sparrows, warblers, finches and swallows that are common, widespread species that play influential roles in food webs and ecosystem functioning from seed dispersal to pest control.
Evidence from the declines emerged from detection of migratory birds in the air from weather radar stations across the continent in a period spanning over 10 years, as well as from nearly 50 years of data collected through multiple monitoring efforts on the ground.
Although the study did not analyze the causes of the declines, it noted that the steep drop in North American birds parallels the losses of birds elsewhere in the world, suggesting multiple interacting causes that reduce breeding success and increased mortality. The largest factor driving these declines is likely the widespread loss and degradation of habitat, especially due to agriculture and urbanization. Other studies have demonstrated mortality from predators, especially free roaming domestic cats; collisions with glass, buildings, and other structures; and pervasive use of pesticides such as neonicotinoids, associated with widespread declines in insects, an essential food source for birds. Climate change is expected to compound these challenges by altering habitats and threatening plant communities that birds need to survive.
More research is needed to pinpoint primary causes for declines in individual species. Until then, the shocking news is a wake up call. According to a recent editorial: “Birds are indicator species, serving as acutely sensitive barometers on environmental health, and their mass declines signal that the earth’s biological systems are in trouble.”
Fortunately, the news is not all bad. There have been a number of promising rebounds resulting from human efforts. Waterfowl (ducks, geese and swans) have made remarkable recovery over the past 50 years, made possible by investments in conservation by hunters and billions of dollars of government funding for wetland protection and restoration. Bald eagles have also made spectacular comebacks since the 1970s, after the harmful DDT was banned (thanks in part to Rachel Carson), and recovery efforts through endangered species legislation in the United States and Canada provided critical protection.
Final Thoughts
Each of us can make a difference with every day actions that together can save the lives of millions of birds – actions like making windows safer for birds by adding or keeping screens up year around, keeping cats indoors, planting more trees, keeping fresh water available and protecting habitat. I just donated to the American Bird Conservancy, a nonprofit organization dedicated to conserving birds and their habitats throughout the Americas. There are other organizations as well, including the Bird Conservancy of the Rockies, the Cornell Lab of Ornithology, Advancing Georgetown and the Smithsonian Migratory Bird Center.
Max Sherman is a medical writer and pharmacist retired from the medical device industry. He has taught college courses on regulatory and compliance issues at Ivy Tech, Grace College and Butler University. Sherman has an unquenchable thirst for knowledge on all levels. Eclectic Science, the title of his column, touches on famed doctors and scientists, human senses, aging, various diseases, and little-known facts about many species, including their contributions to scientific research. He can be reached by email at [email protected].
And flowers through the grass
Joyously sang,
While the tribes of birds sang.
Walther von der Vogelweide’s poem “Dream Song,” written almost 900 years ago extols the virtues of the wide variety of songbirds – birds that are one of earth’s treasures. It would be difficult imagining a world without them.
Rachel Carson, in her prophetic book “Silent Spring” in 1962, wrote about losing birds thusly: “On the mornings that had once throbbed with the chorus of robins, catbirds, jays, wrens, and scores of other bird voices, there was now no sound.”
Her concern was the widespread use of pesticides, and scientists this past month have documented that North America since the 1970s has lost nearly 3 billion birds, about 30 percent of the total. Pesticides are only partly to blame.
Findings raise fears that some familiar species could go the way of the passenger pigeon, a species once so abundant that its extinction in the early 1900s seemed unthinkable. I have written about passenger pigeons before noting that “in the 1800s and before, migratory flocks of passenger pigeons were so immense that they blanketed the skies of eastern North America. One individual recounted a mile wide swath passing overhead blocking the sun for three consecutive days. The birds flew at an estimated speed of about 60 miles an hour. Nesting birds took over entire forests, trees were crammed with dozens of nests, collectively weighing so much that branches would break and tree trunks would topple. Surface vegetation was destroyed by the thick layers of the bird's excrement. Sound was overwhelming. But the birds were not just noisy, they were tasty too, and their arrival guaranteed an abundance of free food.”
The greatest current losses have occurred to birds living along shorelines and in grasslands. They have declined by 53% since 1970, a loss of 700 million adults in the 31 species studied, including meadowlarks, and northern bobwhites. Shorebirds such as sanderlings and plovers are down by about one-third. Habitat loss may be partly to blame. Of the nearly 3 billion birds lost, 90 percent belong to 12 bird families, including sparrows, warblers, finches and swallows that are common, widespread species that play influential roles in food webs and ecosystem functioning from seed dispersal to pest control.
Evidence from the declines emerged from detection of migratory birds in the air from weather radar stations across the continent in a period spanning over 10 years, as well as from nearly 50 years of data collected through multiple monitoring efforts on the ground.
Although the study did not analyze the causes of the declines, it noted that the steep drop in North American birds parallels the losses of birds elsewhere in the world, suggesting multiple interacting causes that reduce breeding success and increased mortality. The largest factor driving these declines is likely the widespread loss and degradation of habitat, especially due to agriculture and urbanization. Other studies have demonstrated mortality from predators, especially free roaming domestic cats; collisions with glass, buildings, and other structures; and pervasive use of pesticides such as neonicotinoids, associated with widespread declines in insects, an essential food source for birds. Climate change is expected to compound these challenges by altering habitats and threatening plant communities that birds need to survive.
More research is needed to pinpoint primary causes for declines in individual species. Until then, the shocking news is a wake up call. According to a recent editorial: “Birds are indicator species, serving as acutely sensitive barometers on environmental health, and their mass declines signal that the earth’s biological systems are in trouble.”
Fortunately, the news is not all bad. There have been a number of promising rebounds resulting from human efforts. Waterfowl (ducks, geese and swans) have made remarkable recovery over the past 50 years, made possible by investments in conservation by hunters and billions of dollars of government funding for wetland protection and restoration. Bald eagles have also made spectacular comebacks since the 1970s, after the harmful DDT was banned (thanks in part to Rachel Carson), and recovery efforts through endangered species legislation in the United States and Canada provided critical protection.
Final Thoughts
Each of us can make a difference with every day actions that together can save the lives of millions of birds – actions like making windows safer for birds by adding or keeping screens up year around, keeping cats indoors, planting more trees, keeping fresh water available and protecting habitat. I just donated to the American Bird Conservancy, a nonprofit organization dedicated to conserving birds and their habitats throughout the Americas. There are other organizations as well, including the Bird Conservancy of the Rockies, the Cornell Lab of Ornithology, Advancing Georgetown and the Smithsonian Migratory Bird Center.
Max Sherman is a medical writer and pharmacist retired from the medical device industry. He has taught college courses on regulatory and compliance issues at Ivy Tech, Grace College and Butler University. Sherman has an unquenchable thirst for knowledge on all levels. Eclectic Science, the title of his column, touches on famed doctors and scientists, human senses, aging, various diseases, and little-known facts about many species, including their contributions to scientific research. He can be reached by email at [email protected].
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