Researchers uncover the secret of giant hummingbirds using miniature trackers

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Scientists recently made an exciting discovery about the world’s largest hummingbird. After attaching tiny backpacks to these birds to study their migration patterns, they found out that this species is actually distinct from another giant species that has been known for centuries.

Researchers have discovered the longest hummingbird migration, a journey that covers a distance of 5,200 miles (8,368 kilometers). This is equivalent to the distance between New York City and Buenos Aires.

The giant hummingbirds of South America have been a topic of interest since naturalist Charles Darwin first encountered them in 1834 during his expedition on the HMS Beagle.

Darwin once observed large hummingbirds breeding along the Pacific coast of Chile, but they disappeared after breeding, leading him to believe they migrated to the Atacama Desert in northern Chile.

Recent studies have shown that there are actually two different types of giant hummingbirds in South America. The northern giant hummingbird resides in the Andes all year round, while the southern giant hummingbird migrates. These two species have been evolving independently for millions of years.

A southern giant hummingbird is seen flying from its breeding grounds in central Chile.

A southern giant hummingbird is seen flying from its breeding grounds in central Chile.

Chris Witt

A new study describing the birds appeared Monday in the journal Proceedings of the National Academy of Sciences.

Lead study author, Jessie Williamson, a National Science Foundation Postdoctoral Fellow and Rose Postdoctoral Fellow at the Cornell Lab of Ornithology in Ithaca, New York, mentioned that the migration patterns of southern giant hummingbirds were previously unknown. They were determined to uncover this mystery.

The researchers aimed to design special backpacks for the hummingbirds to track their movements during migration.

Giant hummingbirds stand out from the hundreds of other hummingbird species in several ways. According to Williamson, these giants are not only much larger (two times or more) than the second largest hummingbird, but their wingbeats and heartbeats are also much slower. Additionally, their wings are proportionately longer, giving them a distinctive appearance in flight that resembles a hovering swift.

Swifts are medium-sized birds that belong to the family Apodidae, which also includes hummingbirds.

Studying hummingbirds, regardless of their size, is a challenging endeavor. The team collaborated with local landowners and residents of villages in Peru and Chile during their fieldwork.

"It's very challenging to capture Giant Hummingbirds," explained Emil Bautista, a researcher at the Centro de Ornitología y Biodiversidad in Lima. "They are very observant and know their territories well. We had to carefully choose where to set up our nets, as they avoid anything unusual."

The research team, led by Williamson, spent nine months camping in rural areas of Chile and Peru. They worked across different terrains, from sea level to the steep slopes of the Andes filled with cacti. During their expeditions, they lived without electricity or running water for weeks at a time.

Williamson came up with a backpack harness that used a jewelry cord to attach a microtracking device to 57 hummingbirds in Chile.

According to Williamson, designing the right backpack harnesses for the giant hummingbirds was a process that took two field seasons. This included trial and error, practicing on a stuffed hummingbird finger puppet, creating a paper maché mock-up geolocator device, and consulting with colleagues experienced in tracking small migratory birds.

A southern giant hummingbird is fitted with a tiny backpack-like geolocator tracking device in central Chile.

A southern giant hummingbird is fitted with a tiny backpack-like geolocator tracking device in central Chile.

Jessie Williamson

The geolocator backpacks weighed 0.3 grams and were designed to be small and light enough so they didn’t interfere with the birds’ style of flight.

Williamson shared her design for attaching devices to hummingbirds in a paper published in the Journal of Avian Biology in June 2021.

According to Williamson, working with hummingbirds can be tricky due to their lightweight bodies, long wings, and short legs. She described them as nature's tiny acrobats.

The researchers needed to recapture the birds in order to collect the data, not just catch them, attach the backpacks, and release them.

To retrieve data from eight of the geolocators, the researchers used fine mesh nets called "mist nets," which are commonly used by ornithologists, according to Williamson.

What the team discovered was that migratory southern giant hummingbirds are like human mountaineers.

High-altitude bird flights

The geolocator data showed that giant hummingbirds on migration can fly up from sea level to over 13,000 feet (3,962 meters) in elevation. Their journey took them as far north as the Peruvian Andes.

Rather than flying straight to these high altitudes, the birds take breaks during their climb, similar to how mountaineers do. They stop for days at a time to let their bodies adjust to the lower levels of oxygen.

Scientists used geolocators and satellite transmitters to follow the migration of birds. They found out that the hummingbirds have the longest known migration, covering a distance of 5,200 miles (8,368 kilometers) from Chile to Peru and back.

During their research, scientists discovered two distinct types of giant hummingbirds by comparing them with genetic information from museum specimens.

Senior study author Christopher Witt, a biology professor and director of the Museum of Southwestern Biology at the University of New Mexico, revealed the mystery behind the migratory giant hummingbirds. These birds had remained elusive as they were often mistaken for non-migratory giant hummingbirds due to their similar appearance. For centuries, researchers and bird enthusiasts were unaware of the distinction between the two species. Thanks to the use of miniaturized trackers, they were finally able to uncover the hidden secrets of these magnificent creatures.

The Rufous Hummingbird has lost two-thirds of its population since 1970.

The Rufous Hummingbird has lost two-thirds of its population since 1970.

Eivor Kuchta/Shutterstock

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A shift in migratory behavior likely led to the distinction between the two species. The researchers examined museum specimens, including one that is 154 years old, and discovered that the giant hummingbird species had been evolving independently for approximately 3 million years.

"It's fascinating to see how different they are from each other, similar to how chimpanzees differ from bonobos," Witt explained. "Although the two species share the same high elevation wintering grounds, it's surprising that the mystery of the Giant Hummingbird went unnoticed for so long, considering they have been evolving separately for millions of years."

The northern giant hummingbird, known as Patagona chaski, lives in the high Andes all year round. It has unique lung and blood capacity compared to the southern giant hummingbird.

The study team discovered that these two birds were actually different species. They decided to name the northern giant hummingbird Patagona chaski, which is a reference to the chaskis, the messengers of the Inca Empire. The word "chaski" comes from Quecha, a group of indigenous languages spoken in Peru and nearby regions.

New discoveries are constantly emerging in the world of birds, shedding light on their fascinating abilities and characteristics. In a recent study, researchers found that Chaski runners were exceptional sprinters with strong agility and stamina. This was attributed to their well-developed lungs and intense aerobic training at high altitudes.

The researchers reported that both populations of giant hummingbirds are stable, and some can even be seen enjoying nectar from backyard feeders.

A southern giant hummingbird is shown poised for take-off.

A southern giant hummingbird is shown poised for take-off.

Chris Witt

Now that we have confirmed the presence of two different species, our team is eager to learn more about how these populations interact, especially when they coexist in the same areas of the Andes during the winter.

"We are interested in understanding where these two forms overlap and how they interact with each other," Witt explained. "Do they compete for resources? Is one species more dominant than the other? How do they share resources, and do they mix together or stay separate within their winter range? There are many intriguing questions that we hope to explore!"

The gold-throated hybrid, center, with its parent species H. branickii (left) and H. gularis (right), in the Field Museum's collections.

The gold-throated hybrid, center, with its parent species H. branickii (left) and H. gularis (right), in the Field Museum's collections.

Kate Golembiewski/Field Museum

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A recently found hummingbird appears to have a golden collar on its neck. Williamson is interested in collaborating with botanists to explore the possible connection between the birds' migration habits and the flowering plants they rely on for food during their travels.

Williamson expressed curiosity about the Southern Giant Hummingbirds and their impressive elevation changes during migration. He compared them to miniature mountain climbers and wondered how they adapt their physiology for these movements.

Editor's P/S:

The article highlights the remarkable discovery of two distinct giant hummingbird species in South America, shedding light on their unique migration patterns and evolutionary history. The use of miniaturized tracking devices has enabled scientists to uncover the hidden secrets of these elusive birds, revealing their incredible resilience and adaptability. The study showcases the power of scientific innovation and collaboration, providing valuable insights into the diversity and behavior of the natural world.

It is intriguing to learn about the northern giant hummingbird's distinct physiological adaptations, such as its enhanced lung and blood capacity, which allow it to thrive in the high Andes all year round. The discovery of these two species raises questions about their interactions and resource utilization within their shared winter range. Further research can provide a deeper understanding of their ecological dynamics and the factors that have contributed to their speciation.