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Swainson's Warbler

Limnothlypis swainsonii ORDER: PASSERIFORMES FAMILY: PARULIDAE

IUCN Conservation Status: Least Concern

One of the most secretive and least observed of all North American birds, the Swainson's Warbler is a skulking bird of the southern canebrakes and rhododendron thickets. If it weren't for its loud, ringing song, the presence of the species in many areas would go completely undetected.

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At a GlanceHelp

Measurements
Both Sexes
Length
5.1–5.5 in
13–14 cm
Wingspan
9.1 in
23 cm
Weight
0.4–0.7 oz
11–20 g
Other Names
  • Paruline de Swainson (French)
  • Verdín de Swainson, Reinita de Swainson (Spanish)

Cool Facts

  • One of the Swainson's Warbler wintering grounds is in the dry limestone forests of Jamaica. During the dry season some birds have trouble finding food there. Because the Swainson's Warbler digs under the leaf litter for insects, it is less affected by the dryness than birds foraging in the forest canopy or on the surface of the ground.
  • The Swainson's Warbler holds a large territory for such a small bird, defending between 3 to 18 ha (7.4-44.5 acres). Measuring exact territory size is difficult, however, because of the extremely dense and vine-entangled habitat used for breeding.
  • The Swainson's Warbler flies directly from perch to perch instead of hopping through the branches like most warblers. It often flies directly across its territory, from one side to the other without stopping in between. On the ground it walks rapidly and rarely hops.
  • The Swainson's Warbler is commonly found in thickets of giant cane, and some researchers have suggested that the plant is essential for the species to nest. Recent work shows, however, that the warbler nests in lowland areas where cane is rare or absent. More important than the exact type of understory plants present is the presence of a thick understory with vine "tents" and tangles, and small shaded glades carpeted with leaf litter.

Habitat


Forest

  • Breeds in southern forests with thick undergrowth, especially canebrakes and floodplain forests in lowlands and rhododendron-mountain laurel in Appalachians.
  • Winters in tropical scrub, evergreen, and gallery forests.

Food


Insects

Insects and spiders.

Nesting

Nesting Facts
Clutch Size
2–5 eggs
Egg Description
White, usually unmarked, but may have faint reddish brown spotting.
Condition at Hatching
Helpless and naked.
Nest Description

Nest a cup of dried leaves, sticks and vines placed low in shrub or vines. Lined with pine needles, hair, grass, Spanish moss, or fern stems.

Nest Placement

Shrub

Behavior


Ground Forager

Forages on ground, probing under leaves and flipping leaves. Frequently sticks its bill into a curled leaf and opens its bill to spread the leaf apart.

Conservation

status via IUCN

Least Concern

Difficult to assess population numbers, but extreme habitat specificity puts species at risk from habitat loss, both on breeding and wintering grounds. Listed on the Audubon Watchlist

Credits

    1. Brown, R. E., and J. G. Dickson. 1994. Swainson's Warbler (Limnothlypis swainsonii). In The Birds of North America, No. 126 (A. Poole, and F. Gill, eds.). The Academy of Natural Sciences, Philadelphia, PA, and The American Ornithologists' Union, Washington, D.C.
    2. Graves, G. R. 2002. Habitat characteristics in the core breeding range of the Swainson's Warbler. Wilson Bulletin 114: 210-220.
    3. Strong, A. M., and T. W. Sherry. 2001. Body condition of Swainson's Warblers wintering in Jamaica and the conservation value of Caribbean dry forests. Wilson Bulletin 113: 410-418.

Range Map Help

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