I’m at Goose Pond Sanctuary, and I hear a buzzing noise. Is it a bumblebee? No! Is it an insect? No! It’s the Clay-colored Sparrow calling! Their call is drawn-out and repetitive, sounding similar to a buzzy insect. This species is described as a small-billed bird, slender in body shape, with a long, notched tail. The Cornell Lab of Ornithology describes their color as “mostly pale, with a tan-and-gray coloration and a contrasting face pattern. The crown on its head is finely streaked, with a pale stripe running over the eye and the cheek a darker color.”
Habitat range map (courtesy of the Cornell Lab of Ornithology).
The Clay-colored Sparrow can be seen frequently at Goose Pond Sanctuary in the restored prairies. Clay-colored Sparrows have different habitat preferences depending on the season. During the breeding season, they are primarily found in open areas. They can occasionally be found in areas with shrubs adjacent to other land cover types (forest edges, waterways, and fields). During winter migration, Clay-colored Sparrows gather in a flock. According to the Cornell Lab, “they gather in flocks of over 100 individuals. Other sparrow species will sometimes join them in migration, including Brewer’s, Chipping, and Lark Sparrows.” The wintering habitat of the Clay-colored Sparrow is similar to their summer breeding habitat: primarily upland plains, though in some areas they can be found in deserts. They are mostly seen in grassy fields and open areas, but remain near shrubs where they can hide from predators.
The female Clay-colored Sparrow builds a nest with the help of the male, who brings her nesting materials. The nest primarily consists of twigs and grass, but can sometimes include animal hair or fur. Nest construction is short, taking as little as two days. The nests are typically quite small, with a diameter of just under two inches. Once the eggs hatch, the young sparrows will hang out on the ground as they learn to fly under the watchful eye of their parents. In another six to eight days, the young fledge and become independent.
Breeding grounds (courtesy of the Wisconsin Breeding Bird Atlas).
Clay-colored Sparrows weren’t always abundant at Goose Pond Sanctuary, making their first appearance in 2008, when one was heard by Goose Pond Sanctuary co-manager Sue Foote-Martin in Browne Prairie. In the first Breeding Bird Atlas, there was only one confirmed nesting pair in Columbia County, near Mud Lake Wildlife Area. During the Breeding Bird Atlas II, the species was found in six of the 85 blocks in the county, including at Goose Pond Sanctuary. The second atlas also revealed more sparrows nesting in southeast and south-central Wisconsin. Today, Goose Pond is considered a hot spot for Clay-colored Sparrows, as is the Sauk Prairie Recreation Area and Horicon Marsh.
Emma Raasch, Graham Steinhauer, and I, along with a group of volunteers, met at Goose Pond Sanctuary in late May to search for active nests that Neil Rettig and Laura Johnson could film for the Cornell Lab of Ornithology. We broke into two teams with Emma and I taking one set of volunteers and Graham taking the rest. From 1–3 PM, we walked transects up and down the prairies, watching for any birds that flushed from hiding. Once a bird was flushed, we searched the area it had flown from for a nest. The main challenges of nest searching are the small size of the nests and how hidden they are in vegetation. Clay-colored Sparrow nests are often in areas with little light penetrating through to avoid detection by predators. They are often less than a foot off the ground, so searching carefully is important to avoid unintentionally disturbing the nest. Luckily, our group found two nests, and Graham’s group also found another. The nests we found were hidden by grasses and forbs, practically on the ground.
A Clay-colored Sparrow nest with three eggs tucked under grasses and forbs (photo by Carolyn Chee).
A Brown-headed cowbird egg in a sparrow nest (photo by Emma Raasch/Madison Audubon).
Something unique we saw in a nest Emma found was a Brown-headed Cowbird egg laid in the sparrow nest. Brown-headed Cowbirds are a native species of Wisconsin that lay their eggs in an already active nest so other birds will raise their young for them. Notice how big the Brown-headed Cowbird egg is compared to the Clay-colored Sparrow egg! Graham’s group found a Blue-winged Teal nest and several Sedge Wrens, but it was too early for the wrens to begin nest building.
Clay-colored Sparrow perched on spiderwort at Goose Pond (photo by Arlene Koziol).
Clay-colored Sparrows are currently abundant, but conservationists are concerned about their populations over the last 49 years—a decline estimated at 51% across the entire species’ range by North American Breeding Bird Survey. Their populations are primarily affected by agricultural practices, including pesticide spraying and land conversion.
Clay-colored Sparrows are fascinating birds and there is much to learn. I only touched briefly on the fascinating facts about this species. To learn more, please visit Cornell Labs, All About Birds. And, if you’re up for a field trip, come out and see the Clay-colored Sparrows for yourself at Goose Pond Sanctuary. We look forward to seeing you here!
Written by Carolyn Chee, masters student at the UW-Madison Nelson Institute of Environmental Studies
Cover image by Kelly Colgan Azar/Flickr. A Clay-colored Sparrow perches on a green flowering shrub with their head up and tail cocked up.
