BIOLOGICAL DATA AND HABITAT REQUIREMENTS
WILDLIFE SPECIES: Anas rubripes | American Black Duck 



TIMING OF MAJOR LIFE HISTORY EVENTS : 
Pair formation - mostly paired by autumn but can continue into winter.
Breeding/Nesting - March through June.
Incubation - 23 to 33 days.
Clutch - 7 to 12 eggs; birds may renest if first clutch is destroyed.
Fledge - 8 to 10 weeks.
Maturity - 1 year.
[10,13]


PREFERRED HABITAT : 
American black ducks prefer coastal brackish marshes and bays with
adjacent agricultural lands [9].  They also inhabit marshy inland lake
shores, sedge (Carex spp.) meadows, bogs, conifer uplands, wet hardwood
forests, and islands in large bodies of water [10,13].  American black
ducks seem to prefer more wooded habitat compared to the mallard [10].
They nest in tree cavities, old bird nests, on muskrat (Ondatra
zibethica) lodges, or on the ground either near water or as far as
one-half mile from the water's edge [10].


COVER REQUIREMENTS : 
During the nesting season American black ducks use wooded areas more
than other dabbling ducks do.  However, because they seem to use a wide
variety of habitats, it is difficult to determine specific requirements
on a broad scale [13].  For brood rearing, American black ducks use
emergent wetlands, marshes, flooded hardwood areas, sloughs, creeks, or
ponds [6].  During winter they usually gather on large bodies of water
or on coastlines where there is abundant plant food [13].

American black ducks use coastal areas or ice-free areas on winter range
for feeding.  They need protection from winter storms; this can be
provided by open water or high banks along open water or large
esturaries [9].  A mix of marine and estuarine habitats offers the
greatest variety of food and cover, although specific data is
unavailable.  For detailed information on habitat suitablity index
models for winter American black ducks refer to Lewis and Garrison [9].
Others have detailed information on determining suitable nesting and
brood-rearing habitat [6].


FOOD HABITS : 
Aquatic invertebrates are the major food for nesting females and young
American black ducks [13].  Other foods include upland grasses, crops
such as blueberries (Vaccinium spp.), oats, buckwheat, corn, and
potatoes.  They also eat clams, mussels, some fish, eelgrass (Aostera
marina), wigeongrass (Ruppia maritima), cordgrass (Spartina spp.),
wildrice (Zizania aquatica), pondweed (Potamogeton spp.), arrowhead
(Sagittaria spp.), burreed (Sparganium spp.), bulrush (Scirpus spp.),
sedge (Carex spp.), and the seeds of oaks (Quercus spp.), baldcypress
(Taxodium distichum), tupelo (Nyssa spp.), and buttonbush (Cephalanthus
spp.)  [9,13].


PREDATORS : 
Humans are the most significant predator of the American black duck
[13].  Other predators include cats (Felidae) and dogs (Canidae); skunks
and weasels (Mustelidae); ravens and crows (Corvidae); opossum
(Didelphis virginiana), raccoon (Procyon lotor), snakes, turtles, and
fish [6].


MANAGEMENT CONSIDERATIONS : 
The American black duck is being replaced by the mallard as the most
important nesting species along the East Coast of North America [4].
Because they use a variety of habitats, it may be best to determine what
areas are used locally and then protect and enhance those areas [6].
Some techniques for improving and creating brood-rearing habitat include
establishing stands of known foods, flooding wetland areas 2 to 24
inches (5-61 cm) deep, and creating visual isolation between feeding
areas to protect against predators [6].  To create nesting habitat
construct level ditches, pits, small dams for runoff ponds, or blast
potholes.  For more detailed information refer to Kirby [6].


REFERENCES : 
NO-ENTRY

Related categories for Wildlife Species: Anas rubripes | American Black Duck