A herald of summer and a connoisseur of that which is sweet and beautiful, the hummingbird is also a little-studied bird that might play a sentinel role in the ecosystems of the Western Hemisphere.
Scientists at the University of Wyoming are hoping to answer some questions about hummingbird populations, and they want to use local birds in their research.
Holly Ernest, UW professor and Wyoming Excellence Chair in Disease Ecology, moved to Laramie in 2014 from the University of California-Davis. She brought with her a love for the tiny birds, which she has been studying for more than eight years.
“Hummingbirds are a major part of our research,” she said. “They’re so diverse and there’s so little we know about them compared to the big mammals.”
Ernest approaches her research with a mindset established by her training as both a veterinarian and an ecologist, applying genetic analysis to learn about population health and biology.
As part of the Hummingbird Health Program in her wildlife genomics and disease ecology lab on campus, she’s working with Ph.D. student Brady Godwin.
Hummingbirds are small, colorful birds from the trochilidae family. They weigh less than a nickel and flap their wings more than 80 times a second, which causes the characteristic humming sound.
They travel quickly from flower to flower, drinking nectar and eating tiny insects while also spreading pollen and serving as a food source for prey species such as raptors.
There are more than 350 species in North, Central and South America, with Wyoming home to species including Rufous, black-chinned, broad-tailed and calliope hummingbirds.
Their health could be affected by the pesticides eaten by the insects they consume and the pollutants in the water found in the nectar they drink. Their feathers contain traces of the heavy metals and other chemicals to which they’re exposed.
“As a sentinel species, they provide indications of overall environmental health,” Ernest said.
Ernest and Godwin are hoping to start building a database of hummingbird health information to serve as a reference for future study. The presence of disease in a population indicates how healthy it is, if there’s a historical comparison.
“We don’t even know what ‘normal’ is for many of our hummingbird species,” she said. “A lot of normal reference ranges haven’t been defined for our hummingbirds.”
DNA analysis is one tool that has a variety of applications. It can be used to determine a bird’s sex and pedigree, for example.
Are birds that congregate together at a feeder related to each other? Are their diseases inherited? Where does one population end and another begin? Are there any subspecies or hybrids that haven’t been classified yet?
“We don’t know until we check their DNA,” Ernest said.
Godwin’s research is focused on Allen’s hummingbird in California and the broad-tailed hummingbird of the Rockies, which has a range that’s naturally patchy. He’s hoping to sample birds across their range to figure out how connected they are.
“That’s a good starting point to get a sense of their ecology,” Godwin said. “That can lead to a lot of other questions.”
Obtaining DNA samples from hummingbirds is no simple task, however. A net is placed over a feeder upon the arrival of a bird, which is then corralled by a scientist and placed in a mesh bag.
The scientist then measures the length of the bill with calipers, weighs the bird, takes a miniscule drop of blood from the toenail, collects a tail feather and attaches a tiny band to the leg.
The band can identify a bird captured later, providing insight into its movement patterns. But the bands are so tiny, about a millimeter wide, that the information on them has to be read with a magnifying glass.
Ernest and Godwin are hoping to continue their research by finding more places to sample birds. They’re looking for busy feeders across Wyoming and Colorado, especially outside Laramie.
“We have a lot of questions to ask,” Ernest said.