Ecology of Red Maple Swamps in the Glaciated Northeast: A ...

census results. Twenty-five (40%) of the 63 species
were encountered in four or more of the seven
studies, The avian community is composed principdy
of facultative species that commonly occur in
upland forests as well. Examples of facultative species
found throughout the region include blackcapped
chickadee, gray catbird, ovenbird (Seiuw
aumpillus), wood thrush (Hyhiehla mustelim),
American robin, and blue jay. Several other breeding
species seem to be attracted to swamps because
of the presence of surface water. Species that are
most strongly associated with northeastern wetland
forests include northern waterthrush
(Fig. 7.2), Canada warbler (Wikonia cadnsis)
(Fig. 7.3), and veery (Catharus fuscescens). Of
these, only the northern waterthrush does not
breed in upland habitats. Canada warblers and
veeries are abundant inforested wetlands in southern
New England, but they also may be found in
stseamside or mesic upland forests, particularly in
other areas of the Northeast (Bent 1953; Bertin
1977; American Ornithologists' Union [AOUj
1983). Prothonotary warblers (Protonotaria citrea)
and cerulean warblers (Lkndroica cerulea) breed in
deciduous forested wetlands, but their ranges encompass
only the western and southern boundaries
of the glaciated Northeast (Bent 1948,1953; AOU
1983; DeGraaf and Rudis 1986).
Raptors are generally secretive, rapid-moving,
and wide-ranging during the breeding season;
therefore, they are seldom recorded in censuses
using spot-mapping or singing male counts (Fuller
and Mosher 1981). Of all northeastern raptors,
Fig. 7.2 Northern waterthwh (Seiurus novebommis),
one of the few species of northeasteRl songbirds that
breed only in forested wetlands. Drawing by R.
m n .
Fig. 7.3. Canada warbler (Wilsonia anadensis), one of
the most abundant breeding birds in southern New
England red maple swamps. Drawing by R. Deegan.
red-shouldered hawks (Buteo lineatus) exhibit the
strongest affimity for forested wetlands, both for
nest sites and for hunting areas (Henny et al. 1973;
Portnoy and Dodge 1979; Rymon 1989). In southeastern
New York and northern New Jersey, northern
goshawks (Accipiter gentilis) have also been
found to select nest sites closer to red maple
swamps than would be expected by chance alone
(Speiser and Bosakowski 1987). The authors noted
that the swamps were relatively undisturbed by
humans and appeared to support a greater density
and diversity of prey species than surrounding
xeric oak forests. Other birds of prey that frequently
inhabit northeastern red maple swamps
include broad-winged hawks (Buteo platypterus),
barred owls (St& varia), eastern screech-owls
(Otus asw), and northern saw-whet owls (Aegolius
acadicus) (AOU 1983; DeGraaf and Rudis 1986;
Rymon 1989).
Factors Affecting Avian Richness and
A bundance
Swift et al. (1984) were the fwst to identify factors
influencing breeding bird communities in
northeastern red maple swamps. They censused
shging males within eight swamps ranging in area
from 30 to 45 ha and measured both vegetation and
hydrologic characteristics within bird census plots.
Using methods adapted from Swift et al. (1984),
Merrow (1990) censused breeding birds in in2 mode
Island red maple swamps ranging in area from 0.5
to 19.3 ha. Merrow compiled two observational
data sets: singing bird observations (i.e., songs of