Scientific Name:
Wilsonia citrina
Nest Type: Cup
Nest Location: Shrub;
1-6', avg. 2-3'
Clutch Size: 3-4
Food: Insects
Foraging Guild:
Foliage gleaner, hawks, ground gleaner
The Hooded Warbler's breeding
range extends east of the Great Plains from southern Michigan east to
southern Rhode Island, and south to the Gulf Coast and northern Florida
(Farrand 1985). In Minnesota, the Hooded Warbler has been recorded in
the east-central, south-central, and southeastern regions of the state,
with records mainly in the Twin Cities area (Janssen 1987). Singing
males had been observed in Clearwater and Scott counties prior to the
discovery of the state's first Hooded Warbler nest at Murphy-Hanrehan
Park in 1984 (Janssen 1987). Due to its scarcity, the Hooded Warbler
has been listed as a species of special concern by the Minnesota Department
of Natural Resources. The Hooded Warbler is a long-distance migrant
that winters from southeast Mexico to Panama (Rappole et al. 1983).
Earliest spring migration dates recorded in Minnesota are April 22 and
30. Only three fall migration dates have been recorded in the state:
August 25, 1983, September 10, 1969, and October 3, 1982 (Janssen 1987).
The Hooded Warbler occupies
mature, moist, deciduous woodland and swamp forests and is particularly
attracted to damp areas formed by seeps, streams, or swamps (Bent 1953,
Robbins 1978). The species is most abundant in mature stands (Noon et
al. 1979, Whitcomb et al. 1981), but is also found in medium-aged stands
(Conner and Adkisson 1975, Robbins 1978). A dense shrub layer, suitable
for foraging and nesting, and scant ground cover are important (Bent
1953, Powell and Rappole 1986). Robbins et al. (1989) identified the
following habitat variables as significant predictors of the species
relative abundance: canopy height, percent of forest within 2 km of
counting point, and foliage density between 0.3 and 1 m.
The Hooded Warbler nests
0.6 to 0.9 m above the ground in dense undergrowth and clutch size ranges
from three to four eggs (Harrison 1975). Females primarily glean insects
from the lower canopy and ground and males hawk insects or sally to
the ground from an elevated perch (Powell and Rappole 1986).
Habitat area may be a limitation
for this species. The Hooded Warbler occurred only in the most extensive
forest in Wisconsin (Ambuel and Temple 1983). In the Washington D.C.
area, the species became extinct in forest fragments that were less
than 1,200 acres (Robbins 1979). In Illinois, Hooded Warblers were not
found in woods smaller than 1500 acres (Blake and Karr 1984). In western
Maryland, the species was detected only in forests larger than 10,000
acres (Anderson and Robbins 1981). In addition to the warblers's shrub
nesting habit, the species is also a frequent Brown-headed Cowbird host
(Ehrlich et al. 1988). Increased forest fragmentation, and the subsequent
increase in cowbirds and predators, may be detrimental to this species
(Brittingham and Temple 1983). Hooded Warblers are therefore best classified
as a forest interior species. Rapid deforestation in Central America,
the principal wintering ground for the species, may also result in a
decline in this and other migrant birds (Powell and Rappole 1986).