World's largest hummingbird is actually two species

An international team of researchers has uncovered not one, but two distinct species of giant hummingbirds. While the northern population resides year-round in the lofty Andes, their southern counterparts embark on migrations to altitudes reaching up to 14,000 feet above sea level during non-breeding periods. Despite their outward resemblance, these species exhibit disparities in their genomes and behaviour.

Described as unique avian specimens, these giant hummingbirds dwarf their ruby-throated counterparts by a staggering eightfold. While previous observations noted the migratory habits of some giant hummingbirds, it was only through comprehensive genome sequencing of both populations that the extent of their distinctiveness became apparent.

The groundbreaking research, heralding the revelation of a second hummingbird species, has been documented in the journal Proceedings of the National Academy of Sciences.

Comparing the two species, researchers likened their differences to the genetic and behavioural distinctions observed between chimpanzees and bonobos. Despite their evolutionary divergence over millions of years, both species maintain residency at high-altitude wintering grounds. The mystery surrounding these giant hummingbirds has persisted, with their distinct identities remaining undiscovered until now.

"They are as different from each other as chimpanzees are from bonobos," said senior author Chris Witt at the University of New Mexico. "The two species do overlap on their high-elevation wintering grounds. It's mind-boggling that until now nobody figured out the Giant Hummingbird mystery, yet these two species have been separate for millions of years. "

Researchers speculate that shifts in migratory behaviour may have contributed to the emergence of distinct species, though the exact trajectory—whether one species gained migratory habits while the other lost them—remains elusive. Before this discovery, only a single species was known within this branch of the hummingbird family tree, while its closest relative, the world's smallest hummingbird, encompasses a diverse array of 165 species.

For simplicity, researchers propose the common names "northern giant hummingbird" and "southern giant hummingbird" for the newly identified species. The Latin name "Patagona gigas" will be retained for the southern migratory species, while the proposed scientific name for the northern population is "Patagona chaskii," with "chaski" meaning "messenger" in Quechua, an indigenous language family spanning Peru and neighbouring regions.

Throughout their research, scientists leaned on the assistance and local knowledge of landowners and villages in Peru and Chile. Acknowledging the significant challenges encountered during fieldwork spanning over 15 years, researchers express gratitude for the support received from the people of a Peruvian village.

"Capturing Giant Hummingbirds is very challenging," he said. "They watch everything and they know their territories well. We had to be strategic in choosing sites for our nets. If Giant Hummingbirds see something unusual, they won't visit that spot. They are more observant than other birds."

Right now, Giant Hummingbird populations, north and south, are stable and the species are common within their ranges -- some even visit backyard nectar feeders. The team plans to continue research on these enigmatic birds.

"We have to figure out where these two forms come together and how they interact," said Witt. "Do they compete, is one dominant over the other, how might they partition resources, and do they mix or spatially segregate within the winter range? Lots of interesting questions to pursue!"

"I'm really interested in how Southern Giant Hummingbirds make such dramatic shifts in elevation during migration. They travel from sea level to the high Andes in just a few weeks," said Williamson. "They're like miniature mountain climbers. How do they change their physiology to facilitate these movements?"