For this year’s annual May fishing trip to Rangeley, Maine, the weather and waters were difficult. We normally have decent fishing while trolling on Rangeley Lake in the early morning hours, since gamefish are still near the shoreline in cold water, chasing smelt. Then we move to local rivers in the afternoon for fly fishing and some years have superb luck, especially if spawning fallfish are in the rivers. Then the brook trout and landlocked salmon move into the rivers to gorge on eggs, and the fishing can be hot.

This year we were met with 35^oF air, intermittent rain and strong winds in combination with strong river flows and water temps near 40^oF, far from ideal conditions. 90 minutes of standing in the river, despite warm clothing and heavy waders, convinced me that the fishing was hard duty. In such circumstances my mind often wanders to the water and forest around me, wondering what wildlife surprises might come my way. Sure enough, a fluttering in the trees along the river pulled me back from my daydream.

For the next 10 minutes I was treated to the sight of dozens of warblers scrambling among the trees and rocks along the shore. These birds were in a frenzy of feeding, jumping along the ground or zipping from branch to branch, clearly in need of food supplies. The birds paid no attention to me, perhaps viewing me as just another standing log close by in the river so I had a front row seat on their antics. I wondered if the bad weather had caused what is known as a fallout, when migrating songbirds are forced to make sudden landings in the face of difficult weather. Depleted from long flights in challenging conditions, birds in a fallout are desperate for sustenance to rebuild their energy reserves before resuming their flights.

Cold and wet spring weather this year seems to have delayed some migrating birds. This mixed flock contained a number of popular warbler species: yellow-rumped, Nashville, magnolia and yellow warblers among them. In addition, I spotted one of my favorite warblers, the peripatetic little fellow in stripes known as the black & white warbler (B&W for short). Let’s learn more about this handsome bird.

The B&W warbler is a striking, easily recognizable songbird found across Maine’s forests each spring and summer. It is well known for its bold, zebra-like streaks and unusual foraging behavior. While many wood-warblers flit restlessly through the high canopy leaves, the B&W commands attention by scaling tree trunks and large limbs, probing bark crevices for hidden insects. In Maine, where diverse northern hardwoods meet vast boreal softwoods, this resilient little insectivore finds an ideal summer home to breed and raise its young.

True to its name, the B&W is cloaked in monochrome colors that set it apart from most of its more colorful cousins among the estimated 115 members of the warbler family Parulidae (known as New World or wood warblers). Adults feature crisp black-and-white striping around their entire body. Males display a black throat and cheek patch, along with a white crown stripe, white eyebrow, and distinct black streaks over a white breast. Females and immatures present a similar but muted pattern, sporting a white or pale cream throat and lighter buff tones on their sides. The tail is short by warbler standards, perhaps to allow them more mobility. A quick sighting may confuse the B&W with the blackpoll warbler but the blackpoll has pale yellow legs, not dark gray, and a large black patch on its head like the black-capped chickadee.

This bird is unique among warblers thanks to its physical adaptation for bark-gleaning. It possesses an unusually long hind toe and sharp claw compared to other warblers, paired with a slightly down-curved bill. These anatomical features allow it to creep up, down, and around tree trunks much like a nuthatch or a brown creeper. It is the only member of its genus, Mniotilta—a name derived from the Greek words for “moss” and “plucking,” perfectly describing the bird’s behavior.

Maine offers a diverse mix of forest types, and the B&W warbler is adaptable across them, although it is primarily found in deciduous and mixed coniferous-deciduous forests. During breeding season, it shows a preference for second-growth woodlands, forest edges, and damp, swampy thickets. In southern and coastal Maine, you will frequently find them in stands of oak, maple, and birch. As you move farther north and east into the North Woods and Down East regions, they readily inhabit mixed forests where mature birches and poplars are interspersed with various conifers.

Because they nest on the ground, like the ovenbirds, a well-developed understory layer is crucial. They favor forests with abundant leaf litter, fallen logs, ferns, and saplings, which provide essential camouflage for their vulnerable nest sites.

While most warblers are foliage-gleaners that snap up insects from the surfaces of leaves and twigs, the B&W benefits from a distinct ecological niche. It moves methodically along the main tree trunk and its larger branches. Its diet consists almost entirely of insects and other arthropods, including caterpillars, beetles, ants, flies and spiders. The bird is also adept at finding insect eggs and pupae hidden in bark crevices.

By mid-to-late May, listen carefully for the high-pitched, rhythmic song of the male B&W warbler as he defends his chosen territory of a few acres and hopes to attract a mate.  The series of thin, squeaky notes has been described as the sound of a wet rag being rubbed vigorously on a windowpane (wesee-wesee-wesee-wesee).

Once a pair bonds, the female selects her desired nesting site. The choice is highly strategic for safety purposes, typically located at the base of a tree trunk, tucked against a downed log, inside a decaying stump, or shielded by ferns or blueberries. The nest is a cup-shaped structure prepared from dead leaves, bark strips, and grasses, then lined with pine needles, moss, or animal hair.

The female lays four to five creamy white eggs with brown or reddish spots. She incubates the eggs alone for roughly 10 to 12 days. Unlike some other songbirds, the male does not bring food to his mate so she must take short breaks to forage before returning to her eggs. Once hatched, the parents share the feeding of their nestlings with a steady diet of soft caterpillars. The young grow rapidly and are capable of flight in just 8 to 11 days, one of nature’s small miracles. Even after leaving the nest, the fledglings linger on the ground and in low shrubbery for another one to two weeks, loudly calling out to their parents for food while they learn the art of bark-creeping.

The diminutive B&W warbler is a long-distance migrant. Its vast breeding range extends from the subarctic forests of northwestern Canada, across the mid-Atlantic states, and down into the American South. In his fine book, Birds of Maine, Peter Vickery notes that B&W Warblers begin their flights to the north in March and arrive here beginning in early April but peak migration is in middle May. Wikipedia notes that vagrant B&W warblers have been spotted in unlikely places like Iceland, Faroe Islands and Ireland.

By late August and September, the birds are ready to fly south once again.  Like many songbirds, they prefer to travel at night using favorable winds. It is common to see or hear them in mixed-species flocks with other migrating songbirds. Scientists can track the birds using radar and sensitive recording devices, in addition to tracking devices on selected birds. In the winter, you might encounter the birds in a variety of landscapes quite different from Maine, from mangrove swamps to coffee plantations.

Because they nest on the ground, eggs and nestlings are vulnerable to predators like red squirrels, chipmunks, raccoons, and weasels. Other woodland predators like garter snakes, blue jays, and American crows also target the nests. Adult warblers must constantly watch the skies for small raptors, particularly sharp-shinned and Cooper’s hawks, which move silently and lethally through dense forest understory.

Peter Vickery notes that the B&W warbler declined rapidly after the 1970s but has been stable in the last 10 years. The bird remains relatively common and is classified as a species of “Least Concern” globally, yet it faces distinct challenges. Forest fragmentation breaks up large tracts of contiguous woodland, creating more “edge” habitat that increases vulnerability to predators and human disturbance. Additionally, as nocturnal migrants, they are susceptible to window collisions with brightly lit buildings (birding groups encourage keeping office buildings dark when possible).

Historically, early American ornithologists were fascinated by this bird’s habits. In the 19th century, it was frequently referred to as the “black-and-white creeper” due to its climbing skills, and some early naturalists debated whether it belonged with the creepers and nuthatches rather than the wood-warblers. Eventually, anatomical studies confirmed its place within the warbler family.

For birders in Maine, finding a black-and-white warbler is a reward for looking past the foliage. Instead of scanning the outermost leaves or the top of the canopy, focus your eyes on the main trunks and large branches of mature trees from the understory up to mid-canopy heights. Listen closely for the high, squeaking song or their sharp chip call note. Enjoy your next encounter with this beautiful, hard-working denizen of the forest.

If you like Ed Robinson’s writing, check out his two Nature Notes books! Click here for more information.