Old Bradley Road in Wicomico County, MD, is like hundreds of other rural roads in the Chesapeake watershed. It’s just a few miles long, runs between farms and forest and is dotted with an occasional house. You can walk along the road with little concern about the sparse traffic.
And like its many rural counterparts, Old Bradley Road’s isolation and varied habitat make it a haven for birds. In little more than an hour one recent morning, I counted a dozen avian species, from indigo buntings to bald eagles. I chided myself for not coming here more often. The modest effort of getting here had been amply rewarded.
Through my binoculars, I was watching one of those birds flick its tiny tail. It was a combination of yellow, black and olive green — the classic blend of colors for the neotropical migrants we call wood warblers.
The green stretched from the forehead all the way to that flicking tail. Although I couldn’t see it, the green back had a series of chestnut streaks. Underneath, the bird was yellow from chin to belly and had yellow wingbars. The face of this male was a complex pattern of warbler colors: A broad yellow eyebrow stood atop a black line through the eye. Under the eye were yellow crescents, and they, in turn, sat atop olive-green arcs. The neck had a messy black patch on the side and the bird’s flanks were streaked with black.
This was a prairie warbler (Setophaga discolor), a common wood warbler in the Eastern United States. Prairie warblers are just a bit more than 4 inches long. A nesting pair and a brood of 3 fledglings (a typical size) would collectively weigh just an ounce.
Females look like males, but are duller overall. They have dark olive-gray patches where males have black ones. The yellows on females are a bit more subdued.
Virtually all prairie warblers spend at least part of the year in the United States. There is even a robust year-round population in central Florida. Most, though, are migratory. They leave their winter Caribbean homes to spread across the Eastern United States — from Connecticut south and west through Missouri and Texas — to breed. They cover the entire Chesapeake watershed except for some of the higher elevations of the Appalachians. (Contrary to their name, these warblers aren’t found on the prairie of our Central States.)
As I watched the tiny bird gleaning for insects, I was amazed anew that such a tiny bird had come so far.
Prairie warblers inhabit scrubby fields and early succession forests where they build their nests and raise their young.
The prairie warbler population boomed from the 1800s as dense forests were felled, opening up their ideal habitat. It continued to grow into the middle of the last century as forests were further fragmented for housing developments and small Eastern farms, and orchards were abandoned as industrial farming exploded in the Midwest.
Today, that trend has reversed. Forests in parts of the region (especially Pennsylvania and New York) are growing back and small farms are starting to reappear. With the loss of their preferred habitat, prairie warblers are declining throughout their range. Population estimates suggest that the prairie warbler population has declined by two-thirds since 1966.
Where they continue to nest, the birds divide breeding responsibilities by gender. And, in what seems to be universally true, females do most of the work. The female prairie warbler builds the nest and does all of the incubation.
The male provides food and protection. Typically, the female lays three to five eggs in daily succession. She’ll incubate them for about 12 days and largely stay with them until they fledge around 10 days later.
Interestingly, the female gobbles all of the egg shells in less than 90 seconds after the eggs have hatched. Presumably, this behavior is designed to keep the nest clean for the chicks, although it may be related to some dietary need. No other wood warbler does this.
As the male I had been watching was demonstrating, prairie warblers eat insects. Their diet consists almost exclusively of insects, spiders and other small invertebrates.
The birds constantly flick their tails when feeding. The action, which displays the white spots on the under tail, startles prey into movements that spell their demise.
The prairie warbler is still common enough if you look in the right habitat. And that flicking tail is a great help in locating the bird in the scrub brush habitat that it prefers.
This natural wonder of Old Bradley Road, I realized, didn’t really require a lot of effort to find, just a willingness to break with my routine. Inertia can be hard to overcome. But each flick of that tail seemed to remind me that small efforts can yield out-sized rewards.