Bird Nests Tell Extraordinary Stories, If You Learn How to Read Them

Casey McFarland, author of “Peterson Field Guide to North American Bird Nests,” describes how paying attention to nests can improve your birding.
A small brown and gray bird perches at the entrance of its dome-like, moss-and-lichen nest, holding plant material in its beak.
Bushtits build elaborate, hanging nests out of soft materials like spiderwebs, mosses, and lichen. Photo: David Moskowitz

One spring, I was taking a walk on a clear morning in western Washington, when a Chestnut-backed Chickadee startled me. She had alighted on a branch just a few feet from my face. After a moment of hesitation, she flitted toward me and, clinging to my chest, began to pull at the woolen fibers of my raggedy sweater. I held my breath. She fluttered to my head and tugged curiously at my hair. The prickling of her delicate claws on my forehead finally made me burst out laughing, and she shot back into the woods, bits of sweater and hair in her beak.

Across the United States and Canada, from the boreal north to Floridian bottomlands, chickadees nest in cavities lined with a soft mattress of mammal fur. That morning, I was the source. At the time, I had no idea what chickadee nests looked like or where they were built. For the first time I wondered. Now, more than 20 years later, I reflect on that experience with a new perspective. I’ve come to appreciate how nests tell extraordinary stories about their makers if you learn how to read them.

Nests teach us how birds think. In a single stretch of forest, Bushtits are experts at finding silk and egg cases from countless spiders with which they build stretchy, socklike nests. A robin finds a mud source to create a clay bowl for her nest’s rigid inner cup. American Dipper nestlings hatch into a ball of green moss built at the edge of a pounding mountain river. And young kingfishers are raised in the darkness of an earthen burrow masterfully excavated by their parents’ oversize, fish-spearing beaks. Each species is hatched onto the same landscape but in entirely different settings, and each of their views of the world is richly varied from the start.

Consider everything mature birds know. The local environment, certainly. They also know other animals that live nearby: black bears, deer, elk, mountain lions and coyotes, woodpeckers and Cooper’s Hawks—a whole community of life. Some species, like my chickadee, may be year-round residents, experiencing their corner of the world from golden summer to the deep cold of winter. Others are migrants who traverse continents. Theirs is an ecological knowledge that spans vast stretches of the planet.

Each nest is a map of one bird’s experience on Earth. It relays how a particular bird sees the place it’s raising young, what materials it looks for, and the location it prefers. And for the many species that fly south for the winter, perhaps to the forests and fields of Mexico or Brazil, the empty nest we find on a cold January day connects us to another part of the planet—evidence in our own backyard of an individual who may, at that very moment, be preening contentedly on a tropical tree branch some 3,000 miles away.

Twenty-odd years ago, I happened to be part of a chickadee’s map. In a tiny way, I was part of her nest, and that experience is now part of my map of the world.

This story originally ran in the Spring 2023 issue. To receive our print magazine, become a member by making a donation today.