New research reveals where N. American bird populations are crashing
Their study, published Thursday in Science, reveals that North American bird populations are being hit hardest in their traditional strongholds, as rapid environmental shifts -- including climate change -- disrupt these once-reliable refuges.
"We have known for a long time that bird populations are declining," lead author Alison Johnston, an ornithologist and ecological statistician at the University of St Andrews, told AFP.
"What we aimed to do here was to look at better population trends in much more detail," she said -- data that is "a lot more tailored for conservation decisions and understanding what we can actually do on the ground."
A landmark 2019 paper also in Science found that North America had lost 2.9 billion breeding adult birds between 1970 and 2017 -- a net loss of nearly a third. The 2025 US State of the Birds report found continued declines in nearly every ecological biome.
Birds play vital roles in ecosystems, from pollinating plants and dispersing seeds to controlling pests.
Their loss disrupts food chains, undermines forest health, reduces crop yields -- and deprives people of the joy of watching species that have long been part of human culture.
But the threats are diverse: from prairie loss impacting Baird's Sparrows in the Midwest to Hawaiian birds threatened by rising seas and invasive predators, including cats.
Johnston and colleagues turned to eBird, an open-source project, analyzing 36 million observations spanning 2007 to 2021 across North America, Central America, and the Caribbean.
A major challenge with citizen science data is separating changes in bird populations from changes in how people watch birds.
The team overcame this with several innovations: using only checklists where observers recorded all species seen; accounting for variables like observation time and distance traveled; and applying a machine learning model that controlled for shifting birding behavior.
They validated the approach through thousands of simulations, ultimately focusing on 495 species for which the results proved reliable.
Unlike previous monitoring that tracked trends at the state or regional level, their analysis looked at plots 27 kilometers by 27 kilometers (17 miles by 17 miles) -- roughly the size of New York City.
Key findings included that 97 percent of species had both areas of increasing population and areas of decline, revealing hidden complexity.
Wood ducks for instance are declining in the Southeast US but thriving farther north, suggesting a climate-related shift.
The study also found that 83 percent of species are shrinking fastest in areas where they were most abundant, particularly grassland and aridland breeders.
The reasons aren't fully known, but one theory is that birds adapted to rich environments may be less resilient to rapid change than those evolved for harsher conditions.
Conversely, some aridland, forest, and generalist species are rebounding in parts of their range where they were once scarce -- pointing to pockets of opportunity.
The findings are already being used by wildlife agencies, for example in permitting wind energy projects to minimize impacts on species such as Bald Eagles.
© 2025 AFP
Hashtags
Try Our AI Features
Explore what Daily8 AI can do for you:
Comments
No comments yet...
Related Articles
AFP
4 days ago
- AFP
Doctors say tetanus still merits vaccination, despite posts downplaying risks
"Tetanus is probably one of the most ridiculous vaccines ever," says the text in an image shared July 30, 2025 on Instagram. "Your chances of getting Tetanus are about the same as walking outta here and getting hit by a meteor." The claim, which also spread on Facebook and X, goes on to allege that applying peroxide to a wound will effectively eliminate the risk of infection and that tetanus "comes from the bowels of animals." "As long as you don't have a sheep or a cow in your house, I don't think you're in any danger," adds the text, which attributes the statement to neurosurgeon Russell Blaylock, who has previously promoted misleading health claims. Image Screenshot of an Instagram post taken August 14, 2025 The posts come as experts say vaccine misinformation is rampant online and may be contributing to falling vaccination rates across the United States and Canada (archived here and here). In a June 2025 video announcing the elimination of funding for a global vaccine body, US Health and Human Services Secretary Robert F. Kennedy, Jr. criticized "whole cell" DTP shots protecting against tetanus, diptheria and pertussis. AFP regularly debunks false vaccine claims and recently fact-checked posts that misled about the Vaxelis 6-in-1 shot, which protects against multiple diseases including tetanus. The claim that the risk of a tetanus infection is almost nonexistent, rendering the vaccines unnecessary, is similarly misleading. Deep wounds Tetanus is an acute infectious disease caused by spores of Clostridium tetani bacteria, according to the World Health Organization (archived here). The bacteria is anaerobic, meaning that after being dormant, it can thrive in environments devoid of oxygen (archived here). This characteristic makes deep wounds the perfect place for the spores to germinate. Barry Pakes, a public health specialist at the University of Toronto, said it is true that cleaning a shallow cut with peroxide or another antiseptic could kill off superficial tetanus-causing bacteria (archived here). "But that's not where the problem is," he said August 7. "The problem is when it gets almost injected into your tissue." He said the "classic" tetanus risk scenario of stepping on a rusty nail is so well known because these types of injuries push spores deep into the flesh, where topical solutions cannot reach them. Once deprived of oxygen, the bacteria begin releasing a toxin that causes tetanus symptoms such as headaches, fevers and seizures (archived here). "Then you become very, very ill and you can potentially die of it," Pakes said. "Like almost everything else, we don't see it often because of vaccination." As with most vaccines, tetanus shots train cells in the body to fortify an immunity response to a specific infection, preventing severe outcomes (archived here). Pakes said tetanus immunization works well in tandem with other vaccines, which is why there are combination shots such as the Vaxelis 6-in-1. Exposure risks Earl Rubin, a pediatric infectious disease specialist at Montreal Children's Hospital (archived here), agreed that vaccination remains necessary and said boosters are recommended roughly every ten years (archived here and here). They can also be administered when a patient comes in with a deep wound and potential exposure to tetanus-causing bacteria (archived here). Rubin also dismissed the claim that exposure to farm animals is the only way people can contract tetanus. "It's a bacteria that's found in the environment, so you don't have to be anywhere near an animal," he said. While the bacteria is found in animal feces, it is also dormant in soil, dust and objects like rusty nails, Rubin explained. AFP has fact-checked more health misinformation here.
France 24
7 days ago
- France 24
Stars in your eyes: Venus and Jupiter visible to the naked eye as summer's best meteor shower peaks
06:35 22/05/2025 Is rise of far right, worldwide, fuelled by decline in people's social skills and social judgement? Science 05/05/2025 Science at a crossroads: Europe positions itself as the gateway to global research Europe 05/05/2025 Trump's 'war' on science and environmental policy will 'delay inevitable transition and cost lives' Europe 09/04/2025 Genetic engineering: Beyond treating disease, where do the 'boundaries' lie? ' Analysis Americas 19/03/2025 European telescope studying the dark universe unveils new images of distant galaxies Science 11/11/2024 This elephant impresses researchers with her 'expressive' technique of showering Europe 25/06/2024 Global first: Chinese lunar probe returns to Earth with rock and soil samples from moon's far side Science 15/05/2024 The Car-T cell revolution: reprogramming lymphocytes against cancer Science
AFP
08-08-2025
- AFP
Major climate-GDP study under review after facing challenge
But a re-analysis by Stanford University researchers in California, released August 6, 2025, challenges the conclusion of the climate paper (archived here and here). It found the projected hit to be about three times smaller and broadly in line with earlier estimates, after excluding an anomalous result tied to Uzbekistan (archived here). The saga may culminate in a rare retraction, with Nature telling AFP August 6 it will have "further information to share soon" -- a move seized upon by climate-change skeptics following the publication of the re-analysis and pre-print correction of the paper. Both the original authors -- who have acknowledged errors in their methodology and data processing -- and the Stanford team hoped the transparency of the review process would bolster, rather than undermine public confidence in science. Climate scientist Maximilian Kotz and co-authors at the renowned Potsdam Institute for Climate Impact Research (PIK) published the original research in April 2024, using datasets from 83 countries to assess how changes in temperature and precipitation affect economic growth (archived here). Influential paper It became the second most cited climate paper of the year, according to the UK-based Carbon Brief outlet, and informed policy at the World Bank, International Monetary Fund, US federal government and others (archived here and here). AFP was among numerous media outlets to report on it. Yet the eye-popping claim that global GDP would be lowered by 62 percent by the year 2100 under a high emissions scenario soon drew scrutiny. "That's why our eyebrows went up because most people think that 20 percent is a very big number," scientist and economist Solomon Hsiang, one of the researchers behind the re-analysis, also published in Nature, told AFP August 5, 2025 (archived here). When they tried to replicate the results, Hsiang and his Stanford colleagues spotted serious anomalies in the data surrounding Uzbekistan. Specifically, there was a glaring mismatch in the provincial growth figures cited in the Potsdam paper and the national numbers reported for the same periods by the World Bank. "When we dropped Uzbekistan, suddenly everything changed. And we were like, 'whoa, that's not supposed to happen,'" Hsiang said. "We felt like we had to document it in this form because it's been used so widely in policy making." The authors of the 2024 paper acknowledged methodological flaws, including currency exchange issues, and on August 6 uploaded a corrected version, which has not yet been peer-reviewed. "We're waiting for Nature to announce their further decision on what will happen next," Kotz told AFP. He stressed that while "there can be methodological issues and debate within the scientific community," the bigger picture was unchanged: climate change will have substantial economic impacts in the decades ahead. Undeniable climate impact Frances Moore, an associate professor in environmental economics at the University of California, Davis, who was not involved in either the original paper or the re-analysis, agreed (archived here). She told AFP on August 5 that the paper's correction did not alter overall policy implications. Projections of an economic slowdown by the year 2100 are "extremely bad" regardless of the Kotz-led study, she explained, and "greatly exceed the costs of reducing greenhouse gas emissions to stabilize the climate, many times over." "Future work to identify specific mechanisms by which variation in climate affects economic output over the medium and long-term is critical to both better understand these findings and prepare society to respond to coming climate disruption," she also noted. Image Riverbank dwellers carry banana produce over the dry Solimoes riverbed in the Pesqueiro community in Manacapuru, Amazonas state, northern Brazil, on September 30, 2024 (AFP / MICHAEL DANTAS, MICHAEL DANTAS) Hsiang said even smaller impacts on GDP should be considered "enough that it makes a lot of sense to invest in reducing climate change." "It's very cost effective," he told AFP. Heat stress on the economy manifests through various mechanisms, he said. For example, workforce productivity dips at high temperatures, risks of potential health complications rise, while machinery also deteriorates (archived here, here and here). "The very hottest countries in the world, near the tropics, we see this effect even more magnified," Hsiang said. "Every one degree of warming for them is a much larger impact on their economy." 'Final stages' Asked whether Nature would be retracting the Potsdam paper, Karl Ziemelis, the journal's physical sciences editor, did not answer directly but said an editor's note was added to the paper in November 2024 "as soon as we became aware of an issue" with the data and methodology (archived here). "We are in the final stages of this process and will have further information to share soon," he told AFP August 6. The episode comes at a delicate time for climate science, under heavy fire from the US government under President Donald Trump's second term, as misinformation about the impacts of human-driven greenhouse gases abounds. Yet even in this environment, Hsiang argued, the episode showed the robust nature of the scientific method. "One team of scientists checking other scientists' work and finding mistakes, the other team acknowledging it, correcting the record, this is the best version of science," he said. AFP has previously reported on other flawed reports and predatory studies on climate change.
