Scientific Name:
Seiurus motacilla
Nest Type: Cup
Nest Location: Ground,
earthen banks; 0-2'
Clutch Size: 4-6;
avg. 5
Food: Aquatic invertebrates,
terrestrial insects
Foraging Guild:
Ground and foliage gleaner, hawks
The breeding range of the
Louisiana Waterthrush extends from eastern Nebraska, east to New England,
and south to eastern Texas, central Georgia, and the Carolinas (Farrand
1985). The species is more abundant in the eastern part of its range
than in the western portion (Coffin and Pfannmuller 1988). The Louisiana
Waterthrush breeds locally in southeast Minnesota along the Mississippi,
St. Croix, and Minnesota River valleys (Janssen 1987). Described as
"common" in these areas in the early 1900s, today it is listed as a
species of special concern by the Minnesota Department of Natural Resources
due to its decline in abundance (Coffin and Pfannmuller 1988). The species
is a long distance migrant, wintering in the West Indies, Mexico, Central
America, and northern South America (Farrand 1985). The warbler arrives
in Minnesota during mid-April to mid-May and leaves during August, with
nearly all individuals gone by mid-September (Janssen 1987).
The Louisiana Waterthrush
inhabits mature deciduous, mixed floodplain, and swamp forests near
swiftly flowing water (Bent 1953, Craig 1985, Bushman and Therres 1988).
Craig (1985) found that in areas of Connecticut where both species of
waterthrush occur, the Louisiana Waterthrush territories ranged from
deciduous lined rocky streams to heavily coniferous swampy streams,
but contained significantly greater areas of fast-moving water and more
deciduous cover. In West Virginia, the Louisiana Waterthrush is common
in all types of deciduous forest, but is strictly limited to streamside
situations (Hall 1983). Robbins et al. (1989) identified the following
habitat variables as significant predictors of the species' relative
abundance: tree basal area, forest area, and moisture gradient. Base
on this information, the species was classified as requiring hardwood
and riparian habitat.
The Louisiana Waterthrush
builds its nest on the ground along stream banks or amid roots of fallen
trees found a few feet from water (Harrison 1975). Clutch size ranges
from four to six eggs, usually five (Harrison 1975). The warbler is
primarily an insectivore, and gleans terrestrial and aquatic insects,
mollusks, crustaceans, and occasionally small fish from the shores of
freshwater streams (DeGraaf et al. 1985, Ehrlich et al.1988).
Habitat area may be a limitation
for this species. A summary by Finch (1991) indicated that the species
was not found in forested tracts of less than 60 acres, while 7500 acres
may be required to guarantee that the species will be present. Whitcomb
et al. (1981) found the Louisiana Waterthrush only in forest fragments
of 175 acres or more in Maryland, and Robbins (1979) estimated the critical
forest size required for this species at 250 acres. However, Robbins
et al. (1989) suggested that the species could likely be a resident
in smaller forests if tracts containing bottomland habitat or streams
were preserved. Based on this information, the species was classified
as an interior forest bird.
Alteration of wooded streambanks
and ravines may be detrimental to the Louisiana Waterthrush (Bushman
and Therres 1988). Forest fragmentation may also have an adverse affect
on this species due to its affinity for extensive forest with little
edge (Robbins 1980, Bushman and Therres 1988). The species is also a
common Brown-headed Cowbird host in some areas (Ehrlich et al. 1988).
In areas of forest fragmentation, the subsequent increase in cowbirds
and predators may be detrimental to this species.