Bird of the Month: Indigo Bunting
Indigo Bunting. Photo by Jeff Bryant.
By Roger Digges, CCAS Vice-President
The month of May brings an influx of late migrants including a small sparrow-sized member of the cardinal family (which also includes grosbeaks, tanagers, and buntings). Like many songbirds, Indigo Buntings are sexually dimorphic when it comes to their plumage. While males are a striking deep blue (or indigo) during breeding season, the female wears a more sensible brown plumage on her back and wings (light color with faint strikes underneath), which help her better blend in with the surroundings as she builds her nest and incubates her eggs. By fall males will exchange their indigo feathers for brown as well.
Where are you likely to find an Indigo Bunting? These summer residents like edges between woodland and open areas, brushy roadsides, hedgerows, and weedy patches. Cathy and I see them at Meadowbrook Park perched on standing dead trees in the Hickman Wildflower Walk area or on the utility wires along Race Street. I’ve found them in many other local parks and forest preserves.
As with most perching birds, you are most likely to hear a male indigo bunting before you see it. Cornell Laboratory of Ornithology’s All About Birds (allaboutbirds.org) describes the male’s vocalizations as “a bright, lively song of sharp, clear, high-pitched notes that lasts about 2 seconds,” and provides several recordings of male indigo buntings singing. If you want a tool you can take with you, I find the free Merlin app from Cornell Lab to be a helpful way to identify bird songs. Note of caution: It isn’t 100% accurate. In March Merlin told me it heard an Eastern Phoebe at Meadowbrook, which I could tell and eventually see was actually a chickadee. (Don’t ask which species of chickadee; see my January 2023 blog in the archives to find out why it’s hard to tell.) Once you’ve located a singing male with your ears, look for him perched high in a nearby tree or shrub, often on an exposed branch, or on a utility wire.
But you may not have to leave home to find an Indigo Bunting. If you’re in the right habitat, you can attract Indigo Buntings with the right bird feeders. They enjoy eating thistle or nyjer seed and mealworms. Now would be a good time to start. After a male successfully mates with a female (or two), the females will build the nest, usually just a few feet above the ground, often in the fork of a tree or shrub. They will weave a cup of leaves, grasses, bark, and stems, then wrap it with spider webs. They line the nest with slender grasses, very small roots, strips of thin bark, thistledown, and maybe deer hair. Once finished, they lay 3 to 4 eggs and incubate them for up to 2 weeks, while the male defends his territory through song. He will also provide females food while they’re on their nests and sometimes their chicks as well. After 1 to 2 weeks, the young birds are ready to leave the nest. Depending on the abundance of insects, females may lay a second or even a third clutch of eggs.
Indigo Buntings leave our area during October, migrating south to Mexico, the Carribbean, and northern South America.
How are Indigo Buntings doing? Like too many of the birds that spend their summers, winters, springs or falls, or live here year-round, their numbers have diminished, in their case by 28% over the past half century, although there are still an estimated 77 million of them. There are many reasons for their decline—habitat loss, far fewer insects, mowing of areas they use, being trapped to be sold as cage birds, and colliding with tall buildings. We can help them by protecting their habitats and using and encouraging the use of dark sky compliant lighting.
