Black-and-white Warbler (Mniotilta varia)

Black-and-white Warbler

[order] PASSERIFORMES | [family] Parulidae | [latin] Mniotilta varia | [UK] Black-and-white Warbler | [FR] Sylvette noir et blanc | [DE] Kletter-Waldsanger | [ES] Reinita Trepadora | [NL] Bonte Zanger

Subspecies

Genus Species subspecies Breeding Range Breeding Range 2 Non Breeding Range
Setophaga varia
Mniotilta varia NA n, e Mexico to Peru, West Indies

Physical charateristics

Slightly smaller than Blackpoll Warbler, with subtly different structure: rather longer bill with noticeably sharp culmen, shorter square tail, and long toes. Rather small but lithe, bark-creeping Nearctic warbler, with black upperparts striped white, and white underparts streaked black; white central crown-stripe diagnostic.

Listen to the sound of Black-and-white Warbler

[audio:http://www.aviflevoland.nl/sounddb/B/Black-and-white Warbler.mp3]

Copyright remark: Most sounds derived from xeno-canto

wingspan min.: 20 cm wingspan max.: 22 cm
size min.: 11 cm size max.: 13 cm
incubation min.: 10 days incubation max.: 12 days
fledging min.: 8 days fledging max.: 12 days
broods: 1   eggs min.: 4  
      eggs max.: 6  

Range

North America : North, East

Habitat

Breeds across cool to warm temperate Nearctic lowlands, on hillsides or ravines in all woodland types from mature deciduous or mixed stands to (more locally) northern conifer forests and also second growth. Forages on main branches or trunks of trees, rather than in foliage.

Reproduction

Mniotilta varia typically breeds between April and August. Males arrive first in the spring. Soon after arriving, they set up territories and begin courting a mate. The courting male pursues the female intermittently over a long period of time, with much song and display of plumage. After pursuing the female, the male will perch near the female with fluttering wings.

The female is the principal nest builder. The nest is a cup, generally on the ground at the base of a tree or fallen log and concealed under dead leaves or branches. The nest is made of leaves, coarse grass, and other fine materials used for lining.
The female lays 4 to 6 (usually 5) white eggs that are flecked with brown and 16 to 18 mm long. Incubation, completed by the female only, takes 10 to 12 days. The male sometimes feeds the incubating female. Both parents feed the young and defend the nest. The young leave the nest 8 to 12 days after hatching. They remain in the parents’ territory for 2 to 3 weeks after fledging. Generally there is only one brood per year, although two broods per year is possible.

Feeding habits

Mniotilta varia creeps along branches and trunks from the canopy to the ground, picking and probing with its thin bill. It often creeps upside-down along the undersides of branches, and may creep downward headfirst. By foraging from bark in this manner, M. varia can glean enough food (including dormant insect forms) before trees leaf out to allow it to arrive at its breeding grounds earlier than other warblers. Though it specializes in bark gleaning, Mniotilta varia also makes use of other foraging behaviors more typical of warblers, including occasional flycatching and foliage gleaning.

Conservation

This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). Despite the fact that the population trend appears to be decreasing, the decline is not believed to be sufficiently rapid to approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is extremely large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.
Breeds in North America east of Rocky Mountains, from north-east British Columbia and south-west Mackenzie east to Newfoundland, south to eastern Texas and central Alabama.
Accidental. Iceland, Faeroes, Britain, Ireland.
Black-and-white Warbler status Least Concern

Migration

Migratory. Winters from northern Mexico and extreme south and south-east of USA south through Central America and West Indies to north-west South America (Venezuela to northern Peru). Probably the most widely common parulid warbler across its winter range. Southward movement extends from Rockies to Atlantic, and even to Bermuda, continuing south through Mexico and Central America as well as across Gulf of Mexico and through Florida. Spring migration is reverse of that in autumn, including both trans- and circum-Gulf movements, on broad front.
Rare autumn vagrant to Atlantic seaboard of west Palearctic, mainly Britain and Ireland where 11 records up to 1995, majority September-October, but noted also March and December.

Distribution map

Black-and-white Warbler distribution range map

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