Black-and-white Warbler

About

The Black-and-white Warbler is a small, distinctive New World warbler known for its striking black and white striped plumage and unique foraging behavior, creeping along tree trunks and branches much like a nuthatch. It is a migratory species, breeding across eastern North America and wintering in the southeastern United States, Central America, and the Caribbean.

Size & lifespan

Length

11-13 cm (4.3-5.1 in)

Wingspan

20-22 cm (7.9-8.7 in)

Weight

8-15 g (0.28-0.53 oz)

Lifespan

Typically 2-5 years in the wild, with a maximum recorded lifespan of over 10 years.

Diet

Insectivore, primarily consuming insects and spiders found on tree bark and foliage.

Physical characteristics

Plumage

Adults are boldly striped black and white over their entire body. Males have more extensive black on the throat and cheeks, particularly during breeding season. Females and immatures are duller, with less black on the throat and flanks, often appearing more grayish-white where males are pure white.

Beak shape

Slender, pointed, and slightly decurved black bill, adapted for probing bark crevices.

Eye color

Dark brown.

Leg color

Dark gray to black.

Distinguishing features

Overall black and white striped appearance, especially on the head, back, and underparts. Two prominent white wing bars. Distinctive foraging behavior of creeping up and down tree trunks and branches.

Juvenile appearance

Juveniles are similar to adult females but are generally duller, with a buffy wash on the underparts and less distinct streaking. Their black markings are often more brownish-black.

Seasonal changes

Males are brightest and most distinctly marked during the breeding season. In non-breeding plumage, males become slightly duller, with some white mottling on the black throat, resembling females more closely. Females show little seasonal change, remaining consistently duller than breeding males.

Sexual dimorphism

Males in breeding plumage have a solid black throat and cheek patch, and heavier black streaking on the flanks. Females have a white throat and less distinct streaking on the flanks, often appearing grayish on the sides of the neck and breast. Non-breeding males resemble females but retain some black on the throat.

How to identify

1. 1

   Plumage Pattern

   Look for the distinctive black and white stripes covering the entire body, including the head, back, and underparts. Males have a solid black throat and cheek patch in breeding season.

2. 2

   Foraging Behavior

   Observe its unique 'creeping' behavior, moving up and down tree trunks and large branches like a nuthatch, rather than flitting through foliage like most warblers.

3. 3

   Wing Bars

   Note the two prominent white wing bars on dark wings, which are consistent across sexes and ages.

4. 4

   Song

   Listen for its high-pitched, reedy, and accelerating 'wee-see, wee-see, wee-see' song, which can be a key identifier, especially when the bird is high in the canopy.

5. 5

   Size and Shape

   It's a small, slender warbler with a relatively long tail and a thin, pointed bill.

Habitat & range

Biomes

Deciduous, mixed, and coniferous forests, particularly mature woodlands.

Geographic range

Breeds across eastern North America, from southern Canada south to the Gulf Coast states. Winters from the southeastern United States (Florida, Gulf Coast), throughout Mexico, Central America, and the Caribbean islands.

Elevation range

Typically found from sea level up to approximately 1,500 meters (5,000 feet), though occasionally higher in some parts of its wintering range.

Preferred environments

Prefers mature forests with a dense understory and abundant large trees, especially those with rough bark. Also found in second-growth forests, wooded swamps, and riparian areas. During migration and winter, they utilize a wider variety of wooded habitats, including shade coffee plantations and suburban woodlands.

Behavior

Activity time

Diurnal.

Feeding habits

Unique foraging style, creeping along tree trunks and large branches, often spiraling up and down, probing bark crevices for insects and spiders. They use their slender bill to extract prey. They also glean insects from foliage and occasionally hawk insects in flight.

Social behavior

Primarily solitary during breeding and wintering seasons. May join mixed-species foraging flocks during migration and in winter.

Flight pattern

Direct and undulating flight, typical of warblers, but often seen in short, quick bursts between foraging spots on trees.

Migration pattern

Long-distance Neotropical migrant. Spring migration occurs from late March to May, and fall migration from late August to October. They migrate primarily at night.

Territoriality

Males establish and defend breeding territories through song and displays. Both sexes defend foraging territories during the non-breeding season.

Breeding & reproduction

Breeding season

Late April to July, with peak activity in May and June.

Nesting habits

Nests are typically built on the ground, often at the base of a tree, stump, or log, or tucked into a mossy bank. The nest is a cup-shaped structure made of leaves, bark strips, moss, and grass, lined with finer materials like hair and rootlets. Built by the female.

Clutch size

3-6 eggs.

Egg description

3-6 (typically 4-5) eggs, creamy white to pale buff, speckled and blotched with reddish-brown or purplish markings, often concentrated at the larger end.

Incubation period

10-12 days, primarily by the female.

Fledging period

8-12 days after hatching, young leave the nest.

Parental care

Both parents feed the nestlings and fledglings. The female primarily incubates, but the male may bring food to her on the nest.

Where to find

Field tips

1. Look on Tree Trunks. Unlike most warblers that forage in foliage, actively scan tree trunks and large branches, especially those with furrowed bark, for their distinctive creeping movements.
2. Listen for the Song. Their high-pitched song can be heard from high in the canopy, often before the bird is seen. Learning this song is crucial for identification.
3. Check Mixed-Species Flocks. During migration and winter, they often join mixed-species foraging flocks, so if you find one warbler, look for others, including Black-and-white Warblers.
4. Patience and Binoculars. They can be difficult to spot due to their small size and tendency to forage high in trees. Good binoculars and patience are essential.

Similar species

Quick facts

Foraging Style:

Creeps on tree trunks and branches like a nuthatch.

Plumage:

Distinctive black and white stripes.

Diet:

Primarily insects and spiders from bark crevices.

Migration:

Long-distance Neotropical migrant.

Nest Location:

On the ground, often at the base of a tree or log.

Fun facts

• The Black-and-white Warbler is sometimes called the 'Black-and-white Creeper' due to its unique foraging behavior, which sets it apart from most other warblers.
• Despite its name, it is not closely related to true creepers (family Certhiidae) or nuthatches (family Sittidae), but rather evolved a similar foraging niche.
• During migration, Black-and-white Warblers can cover vast distances, often flying across the Gulf of Mexico in a single night.
• Males often arrive on breeding grounds several days before females to establish territories.

Scientific classification

Kingdom

Animalia

Phylum

Chordata

Class

Aves

Order

Passeriformes

Family

Parulidae

Genus

Mniotilta

Species

Mniotilta varia

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