“Western Birds,” the journal of western field ornithologists, recently published two articles from the Intermountain Bird Observatory about the expanding range of the Anna’s hummingbird. Historically, the species resided in Baja California. Over the last 80 years, the birds’ range has grown to include the Pacific coast, Oregon and Washington, and now, Idaho.
Since 2015, IBO researchers have banded 50 Anna’s hummingbirds that spend their winters in the Treasure Valley and the West Central Mountains. Researchers give each hummingbird a unique color-mark. These marks let researchers identify birds that have returned to the same sites over successive winters.
Black-chinned hummingbirds are the most common species of hummingbird in the Treasure Valley. Calliope, rufous, and broad-tailed hummingbirds commonly nest in the Idaho mountains. Hummingbirds are generally in Idaho from mid-April to September. The Anna’s hummingbirds, though, appear to follow a different schedule, visiting Idaho from October to March.
The IBO’s first paper, Monitoring Through Community Science: Anna’s Hummingbird Winter Range Expansion into Idaho, was written by Jessica J. Pollock, Heidi Ware Carlisle, Heather M. Hayes and Bryce W. Robinson.
The researchers found that the birds’ range expansion isn’t due to climate change alone. Rather, the birds have thrived because they are well-suited for human-created habitats like cultivated yards and gardens. Researchers relied on citizen scientists – local birdwatchers – to spot hummingbirds and collect data, said Ware Carlisle, IBO education and outreach director.
“A true community effort,” said Ware Carlisle.
The second paper, First Documentation of Successful Breeding for The Anna’s Hummingbird in Idaho, written by Bryce W. Robinson, Jessica J. Pollock, Heidi Ware Carlisle, Heather M. Hayes, and Janice Engle, documents the first Anna’s hummingbird nest found in the state.
“This nest might be a clue that soon we will have Anna’s hummingbirds in the Treasure Valley year-round, instead of only in the winter,” said Ware Carlisle.
Homeowner Janice Engle, a co-author on the paper along with IBO scientists, first discovered and thoroughly documented the nest on her property in the Boise foothills.