Bird of the Month: American Tree Sparrow
A rusty cap and a big heart
Like many of the birds covered in Bird of the Month, the American Tree Sparrow (banding code ATSP) breeds in the northernmost reaches of North America and overwinters from lower Canada to northern North Carolina, Texas, and Arizona. That area, delightfully, includes our region.
Named by early European settlers because it resembled the Eurasian Tree Sparrow they were familiar with, the American Tree Sparrow is a 6-inch bird with a rusty cap, a multi-colored mantle with prominent white wing bars and a two-toned bill (dark upper and yellow lower). Their faces are gray with rufous lines that cut across the eyes.
One important field mark that helps distinguish it from similar sparrows is a dusky spot in the center of a buffy, un-streaked breast. This spot is sometimes referred to as a "stick pin" or heart.
Unlike the sexually dimorphic Red-breasted Mergansers that I wrote about last month, these birds are sexually monomorphic, meaning both the male and female adults have the same-colored plumage and features.
I saw my first American Tree Sparrow on a winter hike with my husband somewhere in southern Erie County or maybe Crawford. We used that central breast spot to help us newbie birders lock in the ID.
If you want to try finding some, you should be looking in fields, marshes, hedgerows, and open forests, which means just about everywhere from Presque Isle to State Game Lands to other undeveloped areas. They are often in small, loose flocks. You may also be lucky enough to find them in residential neighborhoods, gardens, and at feeders. We've only had one American Tree Sparrow in our bird-friendly midtown back yard that we know of. We wish for more.
This species is classified as of Least Concern by conservation groups since it is abundant, but it does face decline. Despite nesting in undisturbed areas and adapting well to human activity while wintering, a 2016 study shows that the population was estimated to have declined by 50 percent between 1970 and 2014. The reasons for this decline are not quite known, but experts speculate that an increase in agriculture, and more forests maturing may have led to loss of open fields and other habitats used by overwintering birds.
So, like many other bird species that are still abundant but decreasing in numbers, American Tree Sparrows face risks that harm their population. This decrease has set off alarm bells for conservationists and other scientists, who are working on ways to stem the loss. Our own efforts can help. Homeowners and land managers can find alternatives to pesticide use, make your space more attractive with native plants and other resources like food and water that support bird life, and keep feline companions indoors.
Look for that rusty cap and "heart" on the breast of any small sparrow you see and you might just get lucky and find this cutie.
Mary Birdsong is the lead shorebird monitor for Erie Bird Observatory. Learn more at eriebirdobservatory.org. Mary can be reached at mbirdsong@eriereader.com
