Giant Hummingbird is in fact two species, according to new research.
There are two populations of Giant Hummingbird – the largest hummingbird in the world. The northern population stays in the high Andes year-round, but the southern population migrates from sea level up to 4,267 m during the non-breeding months.
While the birds from these two populations appear identical, genomes tell a different story and, coupled with the greatly differing migratory behaviour, suggest a split into two species.
This bird is from the sedentary population of the proposed Northern Giant Hummingbird (Marc FASOL).
Migratory hummingbirds
A paper announcing the proposal was published in the journal Proceedings of the National Academy of Sciences. Lead author Jessie Williamson, a National Science Foundation Postdoctoral Fellow and Rose Postdoctoral Fellow at the Cornell Lab of Ornithology, said: "These are amazing birds. They're about eight times the size of a Ruby-throated Hummingbird.
"We knew that some Giant Hummingbirds migrated, but until we sequenced genomes from the two populations, we had never realised just how different they are."
Senior author Chris Witt from the University of New Mexico added: "They are as different from each other as chimpanzees are from bonobos. 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."
Geolocators and satellite transmitters
At first, the research goal was simply to learn where the migratory population went – a journey tracked with geolocators and satellite transmitters. The researchers actually tracked eight individual hummingbirds migrating up to 8,368 km from the Chilean coast up to the Andes of Peru and back – one of the longest hummingbird migrations in the world.
The authors say the shift in migratory behaviour is what drove speciation, though there's no way to tell whether migratory behaviour was gained by one species or lost by the other. Until now, there had been only one known species on this branch of the hummingbird family tree, while Giant Hummingbird's closest relatives diversified into 165 distinct species.
The researchers are proposing straightforward common names: Northern Giant Hummingbird and Southern Giant Hummingbird. The migratory southern species will retain the scientific name, Patagona gigas. The proposed scientific name for the resident northern population is Patagona chaski. 'Chaski' is Quechua for 'messenger'.
This 'Giant Hummingbird' is from the migratory southern population, with the proposed name Southern Giant Hummingbird (Marc Fasol).
Future research
Right now, both Giant Hummingbird populations are stable and the taxa are common within their ranges – some even visit nectar feeders.
"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!"
Reference
Williamson J L, et al. 2023. Extreme elevational migration spurred cryptic speciation in giant hummingbirds. Proceedings of the National Academy of Sciences. DOI: 10.1073/pnas.2313599121
