The Alarming Decline: North America's Birds Vanish at an Alarming Rate
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Introduction to the Crisis
A striking new study reveals that bird populations in Canada and the United States have plummeted by an average of 29% since 1970. This alarming trend has led to the loss of approximately 2.9 billion birds, predominantly affecting common species like sparrows, finches, and warblers.
"Numerous independent sources indicate a drastic drop in bird numbers," stated Ken Rosenberg, an ornithologist and the study's lead author from the Cornell Lab of Ornithology and the American Bird Conservancy. He added, "While we anticipated ongoing declines among threatened species, this research uncovered significant losses among everyday birds in all environments, including those found in our backyards."
Collaborating with experts from Canada's environmental agency and the U.S. Geological Survey, Dr. Rosenberg's team assessed the loss of birds across North America. Birds are recognized as one of the most closely monitored animal groups globally, largely due to longstanding citizen science initiatives such as the Breeding Bird Survey and the Christmas Bird Count.
Video Insight
The video titled "The Disappearance Of North American Birds and What We Can Do About It" delves into the significant factors contributing to this decline and offers actionable steps for conservation.
The Broader Ecological Impact
The researchers noted that the decline in bird populations serves as a critical indicator of environmental health. According to co-author Peter Marra, "The rapid decline of birds indicates that human activities are severely disrupting natural systems across the U.S. and Canada, compromising their ability to sustain diverse wildlife."
He emphasized the urgency of addressing immediate threats, stating, "The cascading effects of these losses could lead to the deterioration of ecosystems vital for human health and livelihoods. Additionally, people globally hold birds in high esteem — can you envision a world devoid of birdsong?"
The study's findings underscore the importance of birds as ecological indicators, revealing a troubling trend of widespread ecological changes. These losses are symptomatic of broader, harmful shifts throughout entire food webs, impacting pollinators, predators, and prey alike. Essentially, wild birds are acting as unintentional indicators of ecological distress in North America.
Video Perspective
In the video "3 Billion Birds Lost," experts discuss the implications of this staggering loss and the urgent need for collective action to reverse the trend.
Methodology of the Study
Dr. Rosenberg and his team compiled their findings from 12 databases containing nearly half a century of data collected from various monitoring projects and citizen science contributions, including the North American Breeding Bird Survey and the Christmas Bird Count.
"Citizen scientists have played a crucial role in gathering data that showcases the extensive losses of bird populations globally," noted co-author John Sauer from the U.S. Geological Survey. "Our results also highlight possible measures to reverse these declines."
The study assessed changes in the populations of 529 bird species, which account for 76% of the breeding birds in North America. By expanding their research to include data from 143 NEXRAD weather radars, the team was able to monitor bird movements during migration periods from 2007 to 2017, revealing a 14% reduction in spring migration over the past decade.
Impact on Various Species
The analysis revealed that nearly 3 billion birds have vanished since 1970, with 12 bird families comprising 90% of the lost species. Grassland birds suffered the most, with a staggering 53% decline, translating to a loss of over 700 million individuals, including 139 million meadowlarks.
The results indicated that a significant 74% of grassland bird species are experiencing declines, likely due to intensified agricultural practices that destroy their habitats and eliminate the insects they rely on for food.
Likewise, forest-dwelling birds have seen a cumulative reduction of over 1 billion individuals since 1970. North American sparrows, often seen in backyards, experienced a loss of approximately 750 million birds. Even common wetland inhabitants like red-winged blackbirds faced a decline of around 92 million.
Shorebirds, already under threat from coastal habitat destruction, also reported a decrease of more than 30%. Alarmingly, even invasive species like the European starling, typically resilient, have faced a 63% decline, raising concerns about environmental health.
Conclusion: A Call to Action
The researchers emphasize that most of the lost birds are common species integral to local ecosystems, contributing to functions like seed dispersal and pest control. The study’s findings indicate a fundamental shift in bird community compositions, with 38 out of 67 surveyed families showing declines.
While some bird families have experienced growth, such as raptors and waterfowl, many others are in peril. The need for conservation efforts is clear, particularly for species lacking advocacy.
Potential conservation strategies include promoting sustainable agricultural practices and encouraging private actions to protect bird habitats.
"It's a wake-up call that we've lost more than a quarter of our birds in the U.S. and Canada," stated co-author Adam Smith. "The challenge extends beyond our borders, as many birds migrate through various countries. A united effort is essential to restore our bird populations."
Source:
Kenneth V. Rosenberg, Adriaan M. Dokter, Peter J. Blancher, John R. Sauer, Adam C. Smith, Paul A. Smith, Jessica C. Stanton, Arvind Panjabi, Laura Helft, Michael Parr, and Peter P. Marra (2019). Decline of the North American avifauna, Science, published online on 19 September 2019 ahead of print | doi: 10.1126/science.aaw1313
Originally published at Forbes on 23 September 2019.