The population of the north is giant hummingbird (Patagona Gigas) According to one report, they remain in the Andean highlands all year round, but southern populations migrate up to 4,200 meters (14,000 feet) above sea level during the non-breeding season. paper Published in Proceedings of the National Academy of Sciences. Although the two species look identical, their genomes and behaviors tell different stories.
The giant hummingbird, found in western South America, is the largest hummingbird in the world.
The species breeds at 39 degrees latitude and above 4,400 m (14,400 ft) above sea level, but this isn't the only time this hummingbird seems to bend the rules of life.
It is the most distinctive of the hummingbirds and has evolved on its own branch over 14 million years.
It has evolved to be roughly twice the size of the next largest hummingbird (17 to 31 g), making its hovering, nectar-feeding lifestyle biomechanically and energetically impossible.
Giant hummingbirds live year-round in the Andean highlands of tropical latitudes. However, southern temperate populations breed at the surface and begin mysterious migrations during the Southern Hemisphere winter.
1834 Charles Darwin witnessed They spring from the “dry deserts of the north,” which refers to the Atacama Desert in northern Chile.
Since then, ornithologists have hypothesized that non-breeding ranges may include the Andes in southeastern Bolivia and northwestern Argentina, but there are also technical challenges in tracking lightweight species and migratory Its travels and non-breeding range remain unknown.
Dr. Jesse Williamson of the University of New Mexico and Cornell Lab of Ornithology and his colleagues wanted to understand where these migratory giant hummingbirds spend the winter.
By attaching small backpack tracking devices to hummingbirds, researchers have shown that giant migratory hummingbirds can ascend to the Andean highlands above 4,000 meters (13,000 feet) and fly as far north as the mountains of Peru. discovered.
This round-trip migration covers more than 8,400 km (5,200 miles). This is approximately the distance between New York City and Buenos Aires.
“It took a lot of trial and error to come up with the right harness design,” Dr. Williamson said.
“Hummingbirds are difficult to handle because they have long wings, short legs, and are light. They are nature's little acrobats.”
One of the researchers' findings was that migratory hummingbirds do not simply fly straight to high altitudes, but pause their ascent for several days to allow their blood and lungs to adapt.
Giant hummingbirds thus employ the same adaptation strategies as human climbers.
“No one could figure out where the migratory giant hummingbirds were going, because they were hidden among the non-migratory giant hummingbirds,” said Christopher Witt, a professor at the University of New Mexico.
“The two forms of giant hummingbirds look almost identical. For centuries, ornithologists and bird watchers never realized they were different.”
“We couldn't have figured this out without the small trackers.”
Genomic sequencing of museum specimens allowed the research team to distinguish between two forms of giant hummingbirds for the first time.
“Natural history collections were absolutely essential to this study,” says Dr. Ethan Gyllenhaal. candidate at the University of New Mexico.
“Including DNA from the 154-year-old type specimen was the key to solving this evolutionary puzzle.”
In fact, these rare historical specimens led the authors to the groundbreaking discovery that migratory birds and giant high-altitude hummingbirds have evolved separately over about 3 million years. This is more than enough time to make them a separate species.
The giant hummingbird population, which lives year-round in the Andean highlands, has larger bodies and significantly different blood and lungs than migratory birds.
Researchers suggest simple common names: Northern Giant Hummingbird and Southern Giant Hummingbird.
Southern migrant species retains its name Patagona Gigas. The proposed scientific name for the northern population is: Patagona Chasky.
“We need to figure out where these two forms combine and how they interact,” says Professor Witt.
“Do they compete, are one dominant over the other, how do they distribute resources, and do they mix or spatially separate within their winter ranges? Should we pursue this? So many interesting questions!”
“We are very interested in how southern giant hummingbirds make such dramatic elevation changes during migration. They travel from sea level to the Andean highlands in just a few weeks,” Dr Williamson said. .
“They're like miniature mountaineers. How do they change their physiology to facilitate this kind of movement?”
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Jesse L. Williamson other. 2024. Extreme high-altitude migration facilitated mysterious speciation in giant hummingbirds. PNAS 121 (21): e2313599121; doi: 10.1073/pnas.2313599121
Source: www.sci.news
