If you were alive in 1970, more than one in four birds in the U.S. and Canada has disappeared within your lifetime. According to published research by journal ‘Science’, wild bird populations in the continental U.S. and Canada have declined by almost 30% since 1970.
Bird numbers fluctuate normally, and that explains changes seen from month to month. But it’s also true that many populations of bird species have been declining gradually and consistently for years.
According to ‘Science’ led by the Cornell Lab of Ornithology “In September 2019, a comprehensive study of 529 bird species in the U.S. and Canada found a net loss of 2.9 billion breeding birds, or 29% of the overall population, since 1970.”
These losses aren’t just restricted to rare or threatened species. In fact, common birds have suffered the greatest losses, including beloved species like Dark-eyed Juncos (down by 168 million) and Red-winged Blackbirds (down by 92 million).
“We were astounded by this net loss across all birds on our continent, the loss of billions of birds,” said Cornell Lab of Ornithology conservation scientist Ken Rosenberg, who led an international team of scientists from seven institutions in the analysis of population trends for 529 bird species. “Our results signal an urgent need…to avert continued biodiversity loss and potential collapse of the continental avifauna.”
The study computes for the first time the total decline in bird populations in the continental U.S. and Canada. There has been a loss of 2.9 billion breeding adult birds. “These bird losses are a strong signal that our human-altered landscapes are losing their ability to support birdlife,” he said. “And that is an indicator of a coming collapse of the overall environment.”
Birds help the environment by pollinating wildflowers, dispersing plants’ seeds and eating pesty insects like bark beetles and weevils; thereby providing balance to ecosystems.
Birds can be seen on radar, especially in spring when they migrate high in the air at night. Cornell Lab of Ornithology aeroecology specialist Adriaan Dokter conducted an analysis of birds visible on radar imagery during nighttime spring migration, and he also found a decline through his studies.
“The amount of ‘bird biomass’ flying over our heads has decreased by about 14% since 2007,” Dokter said. According to the analysis, the declines were steepest among radar stations in the eastern half of the country.
The scale of loss portrayed in this ‘Science’ study is unlike anything recorded in modern natural history. While the Passenger Pigeon likewise suffered cascading losses, that was a population loss among one species, mostly in eastern NA. This current research portrays massive losses among hundreds of species of birds from coast to coast.
The population models in this study are based on several decades of standardized bird-survey datasets. “This research represents the most robust synthesis of long-term population monitoring data ever assembled for animals,” said Adam Smith, a biostatistician for Environment and Climate Change Canada.
“It’s safe to say that in the natural world, birds are the best studied group of wildlife species,” Smith said. “With this study, we have finally managed to come up with a way to estimate the number of birds in North America, to get to a point where we trust the math. And it turns out, in over less than a single human lifetime, we’ve lost almost a third of our birds.”
Forests alone have lost 1 billion birds. Grassland bird populations collectively have declined by more than 50%, or more than 700 million birds. Habitat loss is likely to be a driving factor in these declines, particularly agricultural intensification and development.
“I think this analysis shows that we’re eating away at the foundations of all of our major ecosystems on the continent,” said Arvind Panjabi, avian conservation scientist at the Colorado-based Bird Conservancy of the Rockies. “These numbers show that the world has changed a lot since 1970.”
For Adam Smith, the numbers call out for a radical shift in conservation strategy. “It’s really a wake-up call for the importance of moving beyond just a single species, endangered species conservation framework,” Smith said. “We rescued the Trumpeter Swan and the Peregrine Falcon, and we should be proud of those successes. But we’re at a stage where, given these extreme declines in so many species, we need to move beyond that framework. These are systems and biomes in serious trouble.” More than 90% of the total loss of birdlife in the U.S. and Canada (more than 2.5 billion birds) comes from just 12 avian families, including sparrows and blackbirds. We’ve Lost Nearly 3 Billion Birds Since 1970.
“These so-called common birds—the species that many people see every day—represent the greatest losses of birdlife.” The Red-winged Blackbird is a common bird with an estimate of more than 170 million red-wings today. But just 50 years ago there were more than 260 million, meaning a third of the entire population has been lost in half a century. Red-winged Blackbirds is just one of the common bird species that is suffering severe, unsustainable losses.
Peter Marra, director of the Georgetown Environment Initiative, points out that the cascading losses among blackbirds have an echo in avian history: “That’s what happened with the Passenger Pigeon, a bird that was really common and nobody thought could ever go extinct.”
“Birds are a bellwether of broader ecological problems, such as habitat loss, pollution and climate change.” The decline of North America’s bird population is an enormous sign we can’t ignore. Monitoring their populations helps us understand the health of our natural environment.
Rosenberg says the findings about common birds are some of the most concerning: “We’re squeezing the planet so hard, in terms of using resources and space. And now we’re reaching this tipping point. We’re squeezing out that last bit of space, the last common birds on the landscape are declining, and we’re losing hundreds of millions of birds.”
Steep declines among birds that people regularly see at bird feeders can be deceptive. The flocks of birds are still there, so most people don’t detect a loss of abundance. “There’s a shifting baseline phenomenon,” said Adam Smith.
“Because the declines are gradual, we lose track of just how abundant these birds used to be.” But the research findings in this analysis are clear: Some of America’s most familiar and beloved backyard birds are rapidly disappearing.
Nature is chaotic. Even without humans some bird species would thrive while others would disappear. But all of “birds’ biggest challenges — habitat loss, pesticides, glass windows, even domestic cats — are man-made.”
Not all the news is dire. Some groups of birds are doing well, because governments and societies have invested in saving them. Raptors, waterfowl, and turkeys show what’s possible when commitments are made to bird conservation.
Hawks and falcons benefited greatly from focused conservation policy, such as Endangered Species legislation and the banning of harmful pesticides such as DDT. The impressive gains among some game birds such as Wild Turkey are due to the effectiveness of dedicated conservation funding and enterprising efforts of hunting groups.
As Rosenberg points out, even if 30% of North America’s birds are lost, there are still 70% left to spur a recovery if conservation measures can be implemented. But action must come soon. None of these major declines are hopeless at this point, but that may not be true 10 years from now if we don’t take steps to slow and stop these downward trends.
The Western Meadowlark, in particular, has lost an estimated 40% of its population since 1970. With steep population declines over the past five decades, meadowlarks unquestionably face an uncertain future. Their distinctive song proclaims spring has arrived and winter has departed. Meadow Larks are Spring and is music to our ears and brings back the sounds of our childhood that always lifted our spirit out of the winter blues. Without their melodic songs, how will we know when Spring has finally arrived…