Witnessed by Charles Darwin in 1834, the giant hummingbird (Patagona gigas) migration has long been a thing of mystery to ornithologists – with great uncertainty as to where they travelled and why one population migrated whilst another did not.
A new study published earlier this week in the Proceedings of the National Academy of Sciences used revolutionary tiny ‘backpacks’ to track the movements of the migratory birds, uncovering an epic 8,400km round-trip that includes a 4,000m ascent over the Andes mountain range.
The research also led to the discovery of an undescribed species.
“We were shocked by the discovery,” says lead author Jessie Williamson, who undertook the study as part of her PhD at the University of New Mexico and Museum of Southwestern Biology.
“We knew we'd found something really exciting when we learned that Chilean birds migrate to the high Andes of Peru. It wasn't until we sequenced genomes that we realized just how profoundly divergent the two are – they've been separate species for millions of years.”
As part of examining how the giant hummingbird had such a broad latitudinal and elevational range, the blood physiology and genomic data of both populations was studied. Whilst both shared the haemoglobin genotype for high altitude, the genomic data revealed that they were as genetically distinct as chimpanzees (Pan troglodytes) and bonobos (P. pansicus) and had diverged between two and three million years ago. As such, the two populations are distinct species.
A close examination of the species revealed subtle differences in throat plumage and in size – with the resident giant hummingbird slightly larger and heavier. These differences can easily be seen on museum specimens, and to an extent when birds are caught, but are much more difficult to differentiate in the field. The study proposes the common English name of northern giant hummingbird for the newly described species, and the scientific name of P. chaski. A chaski (or chasqui) was a runner in the Inca Empire, who acted as a messenger and deliverer of small packages.
“There are so many topics we're excited to study,” says Williamson. “We're currently pursuing follow-up work about their competitive dynamics, interactions with Andean plants, shifts in elevation and stopovers along the Andes, and several other aspects of ecology and behaviour.”
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