Kentucky Warbler (Oporornis formosus)

Kentucky Warbler

[order] PASSERIFORMES | [family] Parulidae | [latin] Oporornis formosus | [UK] Kentucky Warbler | [FR] Gorge-jaune du Kentucky | [DE] Kentucky-Waldsanger | [ES] Chipe patilludo | [NL] Kentucky-zanger

Subspecies

Monotypic species

Physical charateristics

Note the broad black sideburns extending down from the eyes, and also the yellow “spectacles.” Sexes similar. Learn the song; ten Kentuckies are heard for every one seen.

Listen to the sound of Kentucky Warbler

[audio:http://www.aviflevoland.nl/sounddb/K/Kentucky Warbler.mp3]

Copyright remark: Most sounds derived from xeno-canto

wingspan min.: 18 cm wingspan max.: 22 cm
size min.: 12 cm size max.: 14 cm
incubation min.: 12 days incubation max.: 13 days
fledging min.: 8 days fledging max.: 10 days
broods: 1   eggs min.: 3  
      eggs max.: 5  

Range

North America : East, Southeast USA

Habitat

Woodland undergrowth.
In summer, prefers deep shaded woods with dense, humid thickets, bottomlands near creeks and rivers, ravines in upland deciduous woods, and edges of swamps. In winter, in the tropics, dependent on dense lowland forests and second growth, mostly in lowlan
ds but also up to 4,000′ in foothills.

Reproduction

During defense of breeding territories, males are persistent singers, singing as often as every 12 seconds. Males may alter their song to match the song of other, nearby territory holders when performing alternating singing bouts.
Nest:
Placed on ground or within a few inches of it; at foot of shrub, in grass tussocks, bedstraw, or goldenrod, or sometimes in the lowest fork of small trees. Nest (constructed by both sexes) is a bulky, open cup of leaves, with a core of weeds, grass stems
; lined with rootlets and hair.
Eggs: Normally 4-5, sometimes 3-6. Creamy white, with brown spots. Incubation is by female only, 12-13 days. Cowbirds often lay eggs in nests of this species.
Young: Nestlings are fed by the female and rarely by the male. Young leave the nest 8-10 days after hatching. Both sexes then feed the fledglings for up to 17 days.

Feeding habits

Mostly insects. Feeds on various insects including moths, bugs, ants, grasshoppers, beetles, caterpillars, aphids, grubs; also spiders, plus a few berries.
Behavior:
Primarily forages by walking on ground, seeking insects among the leaf litter, flipping over dead leaves, sometimes leaping up in the air to glean insects from the underside of foliage. In winter in the tropics, sometimes accompanies army ant swarms, pick
ing up insects that flee the ants. Individuals defend small winter feeding territories.

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.
Kentucky Warbler status Least Concern

Migration

Eastern United States (west to Texas). Winters Mexico to northern South America. In West, a casual stray through southwestern border states to California. Accidental in Nevada, Colorado, Wyoming, Montana, Saskatchewan, Alaska. Migration:
Migrates mostly at night. Many fly across the Gulf of Mexico in spring and fall. Often departs from breeding grounds during August.

Distribution map

Kentucky Warbler distribution range map

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