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taylorvich [soylentnews.org] writes:

https://phys.org/news/2023-12-reveals-secret-sites-america-migrating.html [phys.org]

Every year, billions of birds migrate thousands of miles from their summer breeding ranges to their warmer wintering ranges and back. However, the question of where these birds stop to rest and refuel along the way has long stumped ornithologists.

Princeton Ph.D. student Fengyi Guo and her colleagues from Princeton and the University of Delaware address this question in a newly published paper by using weather radar imagery to map the birds' migratory stopover sites in North America.

Using weather surveillance radar to compute and compare bird movement patterns across five years of spring and fall migrations, Guo and her team pinpointed over 2.4 million hectares of land as key stopover hotspots for land birds across the eastern United States.
...
The radar imagery showed that stopover hotspots along the eastern U.S. consist primarily of deciduous forests, including forest fragments in broadly deforested regions. These hotspots serve as crucial pitstops for large numbers of land birds each year. Protecting these sites helps to ensure the long-term viability of all the bird species that sojourn at these sites.

However, only half of the currently protected hotspots are free from any form of extractive resource use, and two-thirds of all identified hotspots lack any formal protection at all. Guo also found substantial seasonal differences in where hotspots were located.

"Most land birds migrate at night, and they typically lift off from their stopover site to continue their journeys shortly after sunset. Weather radar actually captures this movement of birds, but it requires a lot of processing of the data," explains Guo.

"Each weather radar actively samples the atmosphere every 6-10 minutes and can detect the take-off of birds up to 80 km in radius. Sampling the nightly take-off patterns gives us the spatial details of the daily stopover habitat use of those transient migrants."

The fast-growing field of radar ornithology provides an invaluable peek at the secret lives of migratory birds at an unprecedented scale. David Wilcove, a C-PREE faculty member and co-author of the paper, explains the importance.

Original Submission