By Bryan Stevens
A small songbird, less than six inches in length, sang a series of shrill notes as it flitted from branch to branch about 40 feet off the ground in a tall tree. A group of about 20 birders lifted their binoculars and reacted with excitement when they focused on the bundle of yellow, black, orange and white feathers.
The unexpected discovery — a Cape May warbler — kicked off a bird walk held at Sycamore Shoals State Historic Park in Elizabethton, Tennessee, on May 12. The date deliberately coincided with this year’s observation of International Migratory Bird Day.
This special day is set aside once a year as a conservation initiative to raise awareness about conserving migratory birds and their habitats throughout the Western Hemisphere. This program is dedicated to international conservation efforts and environmental education in Canada, the United States, Mexico, Central and South America, and the Caribbean.
The Cape May warbler wasn’t the only warbler found on the morning walk. Like bookends, a sighting of a blackpoll warbler, a long-distance migrant with black and white feathers, took place near the conclusion of the walk with the same level of excitement that the discovery of the Cape May warbler generated at the walk’s start.
Slightly fewer than half of the world’s 116 warbler species make their home in North America for only a few months out of the year. The others range throughout the Caribbean, as well as Central and South America. Most of them are noted for leading fast-paced, energetic lives. For that very reason, warblers pose a challenge for people wishing to draw them closer by peering at them through binoculars.
Several dozen species of warblers pass through Southwest Virginia, Northeastern Tennessee and Western North Carolina each spring. Some of these birds end their journey in the region, content to build nests and raise young in the Appalachian Mountains and surrounding valleys and foothills. Springtime offers a great opportunity to glimpse many of these small, energetic and often colorful songbirds. It’s always an exciting and memorable moment to focus my binoculars on species ranging from Blackburnian warbler and common yellowthroat to bay-breasted warbler and Northern parula.
Becoming a dedicated “warbler watcher” is a bit of a challenge for several reasons. At the top of the list is the aforementioned pace of the average warbler’s lifestyle. These birds are constantly in motion. Observing and identifying warblers is sometimes accomplished one glimpse at a time while tilting one’s neck back at impossible angles to focus binoculars on tiny birds only a few inches long as they flit through the treetops. Get enough glimpses of that bird skillfully hiding behind autumn foliage and you’ll soon learn to identify the individual species.
Entire field guides have been written offering helpful hints and emphasizing characteristic field marks to make the task of spotting and identifying these birds somewhat simpler, especially for beginners. In birding, there are other challenging families of birds, including shorebirds and sparrows. These others are often studies in subtlety. For the most part, however, warbler’s aren’t subtle. Many of them sport bright and gorgeous plumage in shades of yellow, orange, green, blue, brown and black. Each species has unique patterns, including facial markings, wing bars (or lack thereof) and other signature traits. Some have unusual behaviors that are diagnostic, such as the up-and-down “tail pumping” of a Northern waterthrush or palm warbler or the tail fanning of an American redstart or female hooded warbler.
The Cape May warbler observed at the spring bird walk most likely spent the winter months in such far-flung locations as the Caribbean, although a few of these warblers migrate only as far south as southern Florida. I saw my first Cape May warbler during a trip in the Bahamas back in January of 1999, years before I ever saw this species locally. In its wintering grounds, the Cape May warbler is known for a love of fruit. It also uses a tubular tongue — an oddity among warblers — to sip nectar from flowers and sugar water from feeders intended for hummingbirds.
The Tennessee Watchable Wildlife website explains the origins of this warbler’s common name, which refers to Cape May, New Jersey, the locality where early American naturalist Alexander Wilson first described the species. Interestingly, according to the website, it was not recorded again in Cape May for more than 100 years.
The Cape May warbler is one of the warblers that does not cut short its migration to nest locally. Instead, it spends the nesting season in the spruce forests of Canada and the northern United States. Its spring passage is usually brief, providing a window of opportunity of only two to three weeks to see this dazzling little bird. Fortunately, Cape May warblers migrate back through the region in the fall, usually at a somewhat less hectic pace.
The Cape May warbler’s scientific name — Setophaga tigrina — identifies the bird as a member of the genus Setophaga and also refers to the black striping against its yellow-orange breast that prompted early naturalists to describe this warbler as “tiger striped.”
The Cape May warbler is dependent on spruce budworms, caterpillars of a family of moths that feeds on spruce needles. When the caterpillars are abundant, Cape May warblers shift their nesting efforts into overdrive. As a result, reproductive success for these warblers is sometimes a matter of feast or famine, depending on the abundance of spruce budworms in the forests where they make their home during the nesting season. The size of the clutch of eggs these warblers lay is even dependent on the presence of these caterpillars. When these larval moths are numerous in a forest, the Cape May warbler may lay as many as nine eggs. In years offering less abundance, a clutch of four eggs is more common.
Other warblers I’ve seen around my home and on birding trips this year have included common yellowthroat, yellow-throated warbler, Northern parula, Blackburnian warbler, American redstart, and black-throated green warbler. Many warblers still continue to migrate through the region during the month of May. As mentioned earlier, some of them will also settle in the region long enough to nest before heading back south in the autumn.
In the eastern United States, I’ve seen all the expected warblers save for a handful of species. I’ve never seen a Connecticut warbler, a species notorious for being elusive and hard to spot, or a cerulean warbler. Two endangered species — the Kirtland’s warbler, with a narrow range in Michigan, and the golden-cheeked warbler of Texas — remain future targets for observation. But, when it comes to warblers, I’m always enchanted by these birds, whether I’m seeing them for the hundredth time or the first. So, get outdoors during the month of May and try your own luck at getting a glimpse into the world of warblers. You may find yourself as captivated by them as I am.