Indigo buntings were seen in exceptional numbers at many area bird feeders this past spring as they stopped by to refuel on their long migratory journey. That is when most people see them creating excitement and interest among feeder watchers leading to numerous questions about the species. One of the most interesting questions is how do they find their way back and forth between wintering and summering areas?

I took an ornithology course from Dr. John Emlen at the University of Wisconsin-Madison. He was an outstanding teacher and one of the reasons I got interested in ornithology. I was especially interested in the mystery of how birds find their way over thousands of miles during migration.

Part of that mystery of bird migration was solved by Emlen’s son, Dr. Steve Emlen, who conducted amazing experiments with indigo buntings leading to a major discovery of how birds find their way during migration, they follow the stars.

Indigo buntings played a central role in Emlen’s series of orientation and navigation experiments conducted on migratory birds during the 1960s. Scientists placed caged buntings inside a planetarium, manipulated star patterns, and noted the directions the birds attempted to fly in response. The results proved that indigo buntings and other nocturnal migrants use the movement of the stars to navigate and find their way during migration. Amazing, indeed!

The indigo bunting is a small migratory species in the cardinal family. It summers and nests in eastern North America and winters primarily in Mexico, Central America, northern South America, as well as in the Caribbean and to some extent in southern Florida. It travels 1,200 miles or more between its wintering and summering grounds, all guided by the stars.

Buntings commonly breed and nest throughout Wisconsin in rural shrubby fields, roadside thickets, overgrown thickets, hedgerows, and along wood edges while avoiding mature forests. Only the female builds the nest, incubates the eggs, and feeds the young while the male sings all day long from the highest perches it can find on the tops of trees or utility wires to advertise and defend its territory.

During the summer, buntings change from a seed-eating diet to a mainly insect-eating diet but will continue to eat some seeds and berries. They lay up to six eggs in a nest in the crotch of a shrub or low tree. The nest is made up of fine grasses, cotton, dried grasses and sometimes hair and feathers. Nests are heavily parasitized by the brown-headed cowbird. The indigo bunting has come up with some ingenious methods to combat the parasitic cowbird who lays eggs in other birds’ nests, so they don’t have to raise their own young.

Indigo buntings will abandon their nest if cowbirds parasitize it, or sometimes they will even build over the cowbird egg(s), or just build a new nest. To avoid parasitism altogether, they will sometimes nest after cowbirds are done laying their eggs in other birds’ nests.

Indigo buntings are an amazingly beautiful bird that grace our bird feeders when they migrate through or nest in our area. They can live up to ten years in the wild, but their lives become all too short when they face the perils of predators including house cats and collusions with wind turbines, windows, and towers during migration, so enjoy them when you see them.

Nature notes

Judy and Larry Gregg in Park Falls have been enjoying a family of orioles coming to their grape jelly feeders. And, amazingly, they have a robin family eating suet, something I have never seen or heard of before. At our Nature Education Center, we watched a family of tree swallows fledge from one of our nest boxes. It was a several-hour event as one by one six young birds got up enough nerve to make their first leap into the air.

(Copyright © 2020 APG Media)

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