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September 18, 2025—Fossil evidence of bird migrations to the Arctic. Plus, RFK, Jr.'s vaccine panel meets today, and how DeepSeek was made. —Andrea Gawrylewski, Chief Newsletter Editor | | Joseph Prezioso/AFP via Getty Images | | To recover small bone and teeth fossils, the team washes fossil-bearing sediments through screens and takes the resulting concentrate back to the laboratory for examination under a microscope. Kevin May | | Today, nearly 200 species of birds make their way to the Arctic every spring to reproduce and then fly south again for the winter. But for a long time researchers wondered when these migratory patterns began. In northern Alaska, paleontologists have discovered more than 50 three-dimensionally preserved bird bone fossils, along with dozens of teeth, many belonging to baby birds. They are evidence that at least three types of birds lived alongside nonbird dinosaurs in Arctic Alaska during the Cretaceous period—birds have been nesting in the Arctic for at least 73 million years, nearly half the time they have existed on Earth. Why this is interesting: The Arctic bird migration is transformative for local environments. Although most Arctic birds are only physically in the Arctic for the breeding season, they spur the success of plants by pollinating flowers and dispersing seeds. They also help to manage insect and rodent populations and, by extension, help to control the spread of disease. Birds carry small organisms, such as plants and insects, over long distances to colonize remote polar regions. In fact, birds are so critical to the success of their habitats that scientists think that birds played a key role in structuring remote ecosystems over eons. What the experts say: Research on Arctic birds continues. "We currently have only circumstantial evidence that they were migrating to the Arctic to breed rather than living there year-round," write paleobiologists Lauren Wilson and Daniel T. Ksepka. "But we may be able to build our case with a technique called stable isotope analysis, which lets us use comparisons of the ratios of different forms, or isotopes, of the same element in an animal's teeth or bones to infer its diet, reconstruct its environmental conditions, and even trace its movements over its lifetime." | | Scientists have rediscovered dozens of three-dimensionally preserved teeth and bones from hatchling birds, including this tip of a beak, from the Arctic Circle in Alaska, showing that birds were reproducing at polar latitude by 73 million years ago. Pat Druckenmiller | | | | |
- Forest ecologist Jennifer Khattar studies how forests in Taiwan grow back after agricultural abandonment, often with her four-legged friend Yang Mei. "I survey for coarse, woody debris, understory vegetation and trees. I keep my eyes open, write down everything I see and look forward to what the data will show me," she says. Even in the heat of summer, she has to stay covered up to avoid being cut by thorns and silvergrass in the undergrowth. It's "sweaty and uncomfortable, but I surrender to the conditions," she says. Nature | 3 min read
| | - One of the easiest, safest and most efficient ways to stay healthy is not specific diets or supplements—it's vaccines, Aimee Pugh Bernard and David Higgins, an immunologist and physician, respectively, wrote in 2024. "Vaccines have been used for centuries," they say. "In the past 50 years, they have saved an estimated 154 million lives worldwide. Mathematical models estimate that a 25-year-old now has a 35 percent greater chance of living to their next birthday thanks to vaccines alone." | 3 min read
| | To fly their often thousands-of-miles migrations, biologists believe birds use a combination of factors to navigate: the position of celestial bodies, the magnetic field of Earth, or even scent. The specifics of this remarkable ability are still somewhat a mystery. To get around, we humans rely, for the most part, on visual cues and the distances between waypoints. Humans may see the world clearly, but to creatures that steer by other senses, we're the ones flying blind. | | —Andrea Gawrylewski, Chief Newsletter Editor | | | | |
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