Introductory
WILDLIFE SPECIES: Anas strepera | Gadwall 



ABBREVIATION : 
ANST

COMMON NAMES : 
   gadwall
   gray duck
   gray mallard 
   gray widgeon
   redwing


TAXONOMY : 
The currently accepted scientific name for the gadwall is Anas strepera
Linnaeus.  There are no recognized subspecies [1,6].


ORDER : 
Anseraformes

CLASS : 
Bird

FEDERAL LEGAL STATUS : 
No special status

OTHER STATUS : 
NO-ENTRY


COMPILED BY AND DATE : 
Julie L. Tesky, February 1993


LAST REVISED BY AND DATE : 
NO-ENTRY


AUTHORSHIP AND CITATION : 
Tesky, Julie L. 1993. Anas strepera. In: Remainder of Citation

WILDLIFE DISTRIBUTION AND OCCURRENCE
WILDLIFE SPECIES: Anas strepera | Gadwall 



GENERAL DISTRIBUTION : 
In North America the gadwall's breeding range extends from southern
Alaska and southern Yukon to the New Brunswick-Nova Scotia border, south
locally to southern California, northern Texas, central Minnesota, and
northern Pennsylvania, and along the Atlantic Coast south to Florida and
the Gulf Coast [6,19].  It also breeds in Iceland, the British Isles,
Europe, and Asia [6].

In North America the gadwall winters from coastal Alaska south to
southern Mexico, the Gulf Coast, and along the Atlantic Coast to
southern New England [6,19].


ECOSYSTEMS : 
FRES14 Oak-pine
FRES15 Oak-hickory
FRES17 Elm-ash-cottonwood
FRES18 Maple-beech-birch
FRES19 Aspen-birch
FRES36 Mountain grasslands
FRES37 Mountain meadows
FRES38 Plains grasslands
FRES39 Prairie
FRES41 Wet grasslands
FRES42 Annual grasslands


STATES : 


    
AL
    
AK
	
AZ
    
AR
    
CA
    
CO
    
CT
    
DE
    
FL
    
GA


    
ID
    
IA
    
KS
    
LA
    
ME
    
MD
	
MA
    
MI
    
MN
    
MS


    
    
MO
    
MT
    
NE
    
NV
    
NJ
	
NM
	
NY
    
ND
    
OH
    
OK



    
OR
    
PA
    
RI
    
SC
    
SD
    
TN
    
TX
    
UT
    
VT
    
VA
	

	
    
WA
    
WV
    
WI
    
WY






    
AB
    
BC
    
MB
    
SK
 





    
MEXICO
    




BLM PHYSIOGRAPHIC REGIONS : 
    1  Northern Pacific Border
    2  Cascade Mountains
    3  Southern Pacific Border
    4  Sierra Mountains
    5  Columbia Plateau
    6  Upper Basin and Range
    7  Lower Basin and Range
    8  Northern Rocky Mountains
    9  Middle Rocky Mountains
   10  Wyoming Basin
   11  Southern Rocky Mountains
   12  Colorado Plateau
   13  Rocky Mountain Piedmont
   14  Great Plains
   15  Black Hills Uplift
   16  Upper Missouri Basin and Broken Lands


KUCHLER PLANT ASSOCIATIONS : 
   K047  Fescue - oatgrass
   K048  California steppe
   K049  Tule marshes
   K050  Fescue - wheatgrass
   K051  Wheatgrass - bluegrass
   K053  Grama - galleta steppe
   K054  Grama - tobosa prairie
   K056  Wheatgrass - needlegrass shrubsteppe
   K057  Galleta - three-awn shrubsteppe
   K058  Grama - tobosa shrubsteppe
   K063  Foothills prairie
   K064  Grama - needlegrass - wheatgrass
   K065  Grama - buffalograss
   K066  Wheatgrass - needlegrass
   K067  Wheatgrass - bluestem - needlegrass
   K068  Wheatgrass - grama - buffalograss
   K069  Bluestem - grama prairie
   K072  Sea oats prairie
   K073  Northern cordgrass prairie
   K074  Bluestem prairie
   K075  Nebraska Sandhills prairie
   K076  Blackland prairie
   K077  Bluestem - sacahuista prairie
   K078  Southern cordgrass prairie
   K079  Palmetto prairie
   K094  Conifer bog
   K098  Northern floodplain forest
   K100  Oak - hickory forest


SAF COVER TYPES : 
    16  Aspen
    17  Pin cherry
    18  Paper birch
    63  Cottonwood
    88  Willow oak - water oak - diamondleaf oak
    89  Live oak
    95  Black willow
   203  Balsam poplar
   217  Aspen
   235  Cottonwood - willow
   252  Paper birch


SRM (RANGELAND) COVER TYPES : 
NO-ENTRY


PLANT COMMUNITIES : 
During the breeding season, gadwalls often inhabit islands in wetland
communities with patches of dense western snowberry (Symphoricarpos
occidentalis), slim nettle (Urtica gracilis), Canada thistle (Cirsium
arvense), rose (Rosa spp.), and brome (Bromus spp.).  Additionally,
gadwalls commonly use areas dominated by cattail (Typha spp.), bulrush
(Scirpus spp.), sedge (Carex spp.), and common rivergrass (Scolochloa
festucacea) [8].  Gadwalls will also use upland cover types of cropland,
pasture and hayland, grassland, and mixed prairie and weed [8,9,16].


REFERENCES : 
NO-ENTRY

BIOLOGICAL DATA AND HABITAT REQUIREMENTS
WILDLIFE SPECIES: Anas strepera | Gadwall 



TIMING OF MAJOR LIFE HISTORY EVENTS : 
Breeding and nesting - The gadwall's breeding season varies but usually
occurs in May through mid-July, somewhat later in the northern regions
and earlier in the south [2,11].

Clutch/incubation - Gadwalls lay 5 to 13 eggs per nest, and incubation
is 24 to 28 days [1,13].

Fledge - Gadwalls fledge 7 to 8 weeks after hatching [6].

Maturity - Gadwalls become sexually mature and acquire their breeding
plummage during their first winter [6].

Migration - Gadwalls are one of the last ducks to arrive on breeding
areas in the spring [1]. Some early dates of arrival for various areas
in North America are as follows [2]:

                Southern Iowa - March 10
                Minnesota, Heron Lake - March 17
                Montana - April 1
                Manitoba - April 23
                Saskatchewan - April 18
                Alberta - May 5


PREFERRED HABITAT : 
Gadwall pairs use wetlands for feeding, loafing, and courtship prior to
nesting [16].  They prefer prairie marshes, sloughs, ponds, or small
lakes in grasslands of both freshwater and brackish habitats.  They
generally avoid wetlands bordered by woodlands or thick brush,
preferring those bordered by dense, low herbaceous vegetation, or with
grassy islands [6,17,19].  Shallow semipermanent prairie marshes are
preferred over deeper marshes, lakes or temporary water areas [6,16].
Sixy one percent of 1,073 gadwall broods observed over a 20-year period
in North and South Dakota were in semipermanent wetlands [16].

Winter habitat - Gadwalls prefer to winter in freshwater, marshy
habitats and slightly brackish estuarine bays [6,19].

Nesting - Gadwalls nest on well-drained sites on islands in lakes,
upland meadows or pastures, alfalfa fields, or on prairies usually
within 150 feet (45 m) of water.  They prefer to nest in uplands rather
than over water [19] and generally select the tallest, densest,
herbaceous or shrubby vegetation available to nest in [16].


COVER REQUIREMENTS : 
For escape cover, gadwalls prefer large areas of open water water rather
than with emergents [16].  Tall, dense vegetation provides good nesting
cover for gadwalls.  As the vegetative cover increases, the potential
for nest establishment and success increases.  Height and density of
vegetation is assumed to be more important than species composition.  In
a California study, most gadwall nests were in vegetation 13 to 36
inches (33-91 cm) tall that provided concealment on all sides and above.
No nests were found in herbaceous cover less than 6 inches (15 cm) tall.
Fifty-one percent of nests in North Dakota nesting fields were in
herbaceous cover from 12 to 24 inches (30-60 cm) tall, while 47 percent
were in cover less than 6 inches (15 cm) tall [16].


FOOD HABITS : 
Gadwalls are almost exclusively surface feeders.  They tend to feed in
rather shallow marshes having abundant aquatic plant life growing close
to the surface [6].  They sometimes feed in stubble fields for grain or
in woods for acorns [19].  They mainly consume leaves and stems of
aquatic plants but also eat insects, mollusks, crustaceans, amphibians,
and fishes [9,16,19].  Aquatic plants commonly eaten by gadwalls include
pondweed (Potamogeton spp.), widgeongrass (Ruppia maritima), saltgrass
(Distichlis spp.), muskgrass (Chara spp.), eelgrass (Zostera marina),
spikerush (Eleocharis spp.), spiked watermilfoil (Myriophyllum spicatum)
and filamentous algae [9,16,19].  The two most prominent plants in the
diet of gadwall in South Carolina are fragrant flatsedge (Cyperus
odoratus) and Carolina redroot (Lachnanthes caroliniana).  Major animal
foods include crustaceans, especially those belonging to the order
Anostraca, and insects, especially adult and larval chironomids
(Chironamidae) [16].

Recently hatched gadwalls in Alberta initially fed on invertebrates but
were essentially herbiverous by 3 weeks of age.  Major animal foods of
ducklings included adult and larval chironamids, water boatman
(Cerixidae), beetles (Coleoptera), and cladocerans (Cladocera).
Important plants in the duckling's diets were pondweed, green algae
(Cladophoracea), duckweed (Lemna minor), and seeds of American
sloughgrass (Beckmannia syzigachne) [16].


PREDATORS : 
Predators of gadwalls include humans, foxes (Vulpes spp.), raccoons
(Procyon lotor), striped skunks (Mephitis mephitis), coyotes (Canis
latrans), badgers (Taxidea taxus), weasels (Mustela spp.), minks
(Mustela vison), crows (Corvus spp.), and magpies (Pica spp.)
[8,9,12,14].


MANAGEMENT CONSIDERATIONS : 
Grazing and mowing often destroy preferred nesting cover for gadwalls.
Although annual mowing or grazing is not recommended, mowing may be
useful for maintaining vegetative cover in earlier, more productive
successsional stages [16].


REFERENCES : 
NO-ENTRY

FIRE EFFECTS AND USE
WILDLIFE SPECIES: Anas strepera | Gadwall 



DIRECT FIRE EFFECTS ON ANIMALS : 
Late spring and summer fires may destroy gadwall nests [20].  Ducklings
and molting adults are especially vulnerable to fire.  When not molting
adult gadwalls can probably easily escape fire.


HABITAT RELATED FIRE EFFECTS : 
Burning can change the growth form and pattern of nesting cover for
gadwalls [20].  Gadwalls prefer nesting in dense cover [16], which can
be destroyed by fire.  A study of the effects of nesting cover removal
on breeding puddle ducks at Lower Souris National Wildlife Refuge, North
Dakota, showed that after spring burning, nest densities of gadwalls
were greater in areas where the vegetation was not burned [12].
Additionally, gadwall nests were significantly (P<0.01) less abundant in
mowed meadows that would be expected by chance.  They made up 29 percent
of all nests found, but only 13 percent of the nests were in mowed
meadows.  Gadwalls will, however, use areas that have been burned if
cover development is sufficent when they begin nesting [12].  Changes in
vegetation cover induced by fire can also benefit gadwalls by destroying
unwanted vegetation and increasing vegetation preffed by gadwalls [15].


FIRE USE : 
Wetlands can be burned to reverse plant succession to a subclimax plant
community which is attractive to waterfowl [15].  Fire can be used to
remove the accumulation of dead vegetation built up on marshes over the
years and restore wetlands that are dominated with plants such as common
reed (Phragmites communis). Desirable gadwall foods such as pondweed can
be restored by burning.  Burning should be postponed until after the
nesting season to avoid destroying nests [15].


REFERENCES : 
NO-ENTRY

REFERENCES
WILDLIFE SPECIES: Anas strepera | Gadwall 



REFERENCES : 

.  Bellrose, Frank C. 1980. Ducks, geese and swans of North America.
       Harrisburg, PA: Stackpole Books. 3rd ed. 540 p.  [19802]

.  Bent, Arthur Cleveland. 1962. Life histories of North American wild
       fowl. Part 1. New York: Dover Publications, Inc. 244 p.  [20027]

.  Bernard, Stephen R.; Brown, Kenneth F. 1977. Distribution of mammals,
       reptiles, and amphibians by BLM physiographic regions and A.W. Kuchler's
       associations for the eleven western states. Tech. Note 301. Denver, CO:
       U.S. Department of the Interior, Bureau of Land Management. 169 p. 
       [434]

.  Eyre, F. H., ed. 1980. Forest cover types of the United States and
       Canada. Washington, DC: Society of American Foresters. 148 p.  [905]

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       1977. Vegetation and environmental features of forest and range
       ecosystems. Agric. Handb. 475. Washington, DC: U.S. Department of
       Agriculture, Forest Service. 68 p.  [998]

.  Johnsgard, Paul A. 1979. A guide to North American waterfowl.
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.  Johnson, Douglas H.; Grier, James W. 1988. Determinants of breeding
       distribution of ducks. Wildlife Monographs. 100: 1-37.  [21350]

.  Hines, J. E.; Mitchell, G. J. 1983. Gadwall nest-site selection and
       nesting success. Journal of Wildlife Management. 47(4): 1063-1071. 
       [21351]

.  Dahlsten, D. L.. 1986. Control of invaders. In: Mooney, Harold A.;
       Drake, James A., eds. Ecology of Biological Invasions of North America
       and Hawaii. Ecological Studies 58. New York: Springer-Verlag: 275-302. 
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.  Kuchler, A. W. 1964. Manual to accompany the map of potential vegetation
       of the conterminous United States. Special Publication No. 36. New York:
       American Geographical Society. 77 p.  [1384]

.  Madge, Steve; Burn, Hilary. 1988. Waterfowl: An indentification guide to
       the ducks, geese and swans of the world. Boston, MA: Houghton Mifflin
       Company. 298 p.  [20029]

.  Martz, Gerald F. 1967. Effects of nesting cover removal on breeding
       puddle ducks. Journal of Wildlife Management. 31(2): 236-247.  [16284]

.  Musgrove, Jack W.; Musgrove, Mary R. 1943. Waterfowl in Iowa. Des
       Moines, IA: State Convservation Committee. 113 p. + index.  [20028]

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.  Schlichtemeier, Gary. 1967. Marsh burning for waterfowl. In:
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.  Sousa, Patrick J. 1985. Habitat suitability index models: gadwall
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.  Springer, Paul F.; Stewart, Robert E. 1977. Gadwall nesting in Maryland.
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.  Vermeer, Kees. 1970. Some aspects of the nesting of ducks on islands in
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.  DeGraaf, Richard M.; Scott, Virgil E.; Hamre, R. H.; [and others]. 1991.
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.  Kruse, Arnold D.; Higgins, Kenneth F. 1990. Effects of prescribed fire
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       management: Proceedings, 1st Interior West Fire Council annual meeting
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.  Donohoe, Robert W. 1974. American hornbeam  Carpinus caroliniana Walt.
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Related categories for Wildlife Species: Anas strepera | Gadwall