Wood warblers are a group of birds unique to the Americas. These small, active and often colorful birds are represented by at least fifty-two North American species, of which forty species have been reported in South Dakota. Most species are long distance migrants, flying amazing distances each spring and fall. Some warblers that nest in Canada winter as far south as Argentina. Most wood warblers are grouped with many other species of long distance migratory birds that are referred to collectively as "neotropical migrants". Each spring and fall, great waves of wood warblers are on the move, to the delight of birdwatchers searching for the beautiful rarities that pass briefly through their favorite warbler watching haunts.

One of the most interesting and unique of the wood warblers is the Black-and-White Warbler. True to its name, this warbler exhibits striking black and white plumage. Males have sharply contrasting black and white patterns while females and immature birds are slightly duller and have less black on the head and throat. This is the only warbler species that regularly forages on tree trunks and limbs, creeping over the bark like a nuthatch. With a slightly decurved bill that is relatively longer than bills of other warbler species, the Black-and-White Warbler probes in the crevices of the bark for dormant insects and insect larvae. The legs are short and stout and the feet are large, much like a nuthatch. The toes have long claws for gripping the bark. The hallux, analogous to the big toe on a human foot but extending back on a bird’s foot, is much longer than hallux of other wood warblers.

All of these adaptations allow the Black-and-White Warbler to forage efficiently on dormant insects that other warbler species can only pick up opportunistically. Because it can take advantage of the early, dormant insect food source, the Black-and-White Warbler is one of the first warbler species to return each spring to the breeding grounds. Black-and-White Warblers are also capable of foraging on active insects, often gleaning aphids from the foliage and snatching insects out of the air. Their main prey is the caterpillars, pupae, and egg masses of moths and some species of butterflies, including those of the introduced pest species, the gypsy moth.

Black-and-White Warblers are both migrant and breeding birds in South Dakota. The birds move through the state each spring to nest in the forests of Canada but some remain to nest in the Black Hills area, the Pine Ridge area, and occasionally in other forested habitats of South Dakota. Black-and-White Warblers also nest in most of the eastern United States. The species winters in Florida, Caribbean islands, Central America and South America south to northern Peru.

Males are highly territorial and are very vocal during the nesting season. The song is a high pitched, repetitive weesy, weesy, weesy…, higher on the first note. The nest is usually built on the ground, in dense forest understory against a stump, rock, log, or other natural feature. Only the female incubates the eggs. She usually lays five eggs but occasionally four or rarely six. Incubation lasts about 10-12 days and the young leave the nest 8-12 days after hatching. The Black-and-White Warbler has only one brood per nesting season.

These warblers are locally common nesting birds in deciduous woodlands of the Pine Ridge area and locally in deciduous woodlands of the lower elevations of the Black Hills. The South Dakota Ornithologists’ Union 2001 spring meeting included a field trip to Yellow Bear Canyon in western Bennett County on May 19 and 20. There, field trip participants were able to hear many singing males and observe the birds in the dense forested canyons of the Pine Ridge area. The Fort Meade Recreation Area southeast of Sturgis is another good area to find nesting Black-and-White Warblers. They are fairly common in the oak forest along Alkali Creek in the vicinity of the horse camp. Late May and June is the best time to look for nesting birds.

Migrants can be seen statewide each spring and fall, wherever trees are present. Spring migrants move through in late April into May and fall migrants from late August into September. The species is commonly seen in migration but usually in low numbers. An alert naturalist should have no trouble finding a few Black-and-White Warblers each spring and fall.

Research proves that the Black-and-White Warbler is highly sensitive to forest fragmentation. However, this species is not as dependent on specific forest types as are many wood warblers. Still, extensive forested areas are a habitat requirement. Researchers have found that at least 740 acres, an area slightly larger than a square mile, of forest habitat is needed to maintain a breeding population of Black-and-White Warblers. Unlike many species of neotropical migrants, Black-and-White Warbler populations seem to be stable but there are areas where significant losses have occurred. One is the Missouri River valley. In 1862 F.V. Hayden wrote of the Black-and-White Warbler "Very abundant along the willow bottoms of the Missouri, as high up as Fort Pierre at least." W. J. Hoffman was an Army surgeon and naturalist at the Grand River Agency, near present day Mobridge, in 1873. Hoffman called this species the black and white creeper but we can be certain he was referring to the Black-and-White Warbler, since he also to referred to it by the scientific name, Mniotilta varia, literally the variegated moss-plucking bird. Hoffman saw several Black-and-White Warblers in June along Oak Creek and on an island in the Missouri River. There are several references to breeding season records of Black-and-White Warblers at Farm Island and other locations along the Missouri River in South Dakota Bird Notes, the South Dakota Ornithologists’ Union official journal.

Black-and-White Warblers were breeding birds in the forests of the Missouri River floodplain. Like other species of deciduous forest birds, the Black-and-White Warbler used the extensive forests of the Missouri River floodplain as nesting habitat. The distribution of many forest species became dendritic on the treeless prairie as they followed the large rivers that provided the required nesting habitat, deciduous forest…a conundrum in the rough as dendritic means branching like a tree. Most of the Missouri River deciduous forest habitat in South Dakota was destroyed or degraded after construction of the Missouri River dams.