Index of Species Information
WILDLIFE SPECIES: Anas strepera
AUTHORSHIP AND CITATION :
Tesky, Julie L. 1993. Anas strepera. In: Fire Effects Information System, [Online].
U.S. Department of Agriculture, Forest Service,
Rocky Mountain Research Station, Fire Sciences Laboratory (Producer).
Available: www.fs.fed.us/database/feis/animals/bird/anst/all.html .
COMMON NAMES :
gray (grey) duck
The currently accepted scientific name for the gadwall is Anas strepera
Linnaeus. There are no recognized subspecies [1,6].
FEDERAL LEGAL STATUS :
No special status
OTHER STATUS :
WILDLIFE DISTRIBUTION AND OCCURRENCE
WILDLIFE SPECIES: Anas strepera
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 .
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].
FRES36 Mountain grasslands
FRES37 Mountain meadows
FRES38 Plains grasslands
FRES41 Wet grasslands
FRES42 Annual grasslands
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 :
17 Pin cherry
18 Paper birch
88 Willow oak - water oak - diamondleaf oak
89 Live oak
95 Black willow
203 Balsam poplar
235 Cottonwood - willow
252 Paper birch
SRM (RANGELAND) COVER TYPES :
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) . Gadwalls will also use upland cover types of cropland,
pasture and hayland, grassland, and mixed prairie and weed [8,9,16].
BIOLOGICAL DATA AND HABITAT REQUIREMENTS
WILDLIFE SPECIES: Anas strepera
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 .
Maturity - Gadwalls become sexually mature and acquire their breeding
plummage during their first winter .
Migration - Gadwalls are one of the last ducks to arrive on breeding
areas in the spring . Some early dates of arrival for various areas
in North America are as follows :
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 . 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 .
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  and generally select the tallest, densest,
herbaceous or shrubby vegetation available to nest in .
COVER REQUIREMENTS :
For escape cover, gadwalls prefer large areas of open water water rather
than with emergents . 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 .
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 . They sometimes feed in stubble fields for grain or
in woods for acorns . 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
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) .
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.)
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 .
FIRE EFFECTS AND USE
WILDLIFE SPECIES: Anas strepera
DIRECT FIRE EFFECTS ON ANIMALS :
Late spring and summer fires may destroy gadwall nests . 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 . Gadwalls prefer nesting in dense cover , 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 .
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 . Changes in
vegetation cover induced by fire can also benefit gadwalls by destroying
unwanted vegetation and increasing vegetation preffed by gadwalls .
FIRE USE :
Wetlands can be burned to reverse plant succession to a subclimax plant
community which is attractive to waterfowl . 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 .
FIRE REGIMES :
Find fire regime information for the plant communities in which this
species may occur by entering the species name in the FEIS home page under
"Find Fire Regimes".
WILDLIFE SPECIES: Anas strepera
1. Bellrose, Frank C. 1980. Ducks, geese and swans of North America.
Harrisburg, PA: Stackpole Books. 3rd ed. 540 p. 
2. Bent, Arthur Cleveland. 1962. Life histories of North American wild
fowl. Part 1. New York: Dover Publications, Inc. 244 p. 
3. 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.
4. Eyre, F. H., ed. 1980. Forest cover types of the United States and
Canada. Washington, DC: Society of American Foresters. 148 p. 
5. Garrison, George A.; Bjugstad, Ardell J.; Duncan, Don A.; [and others].
1977. Vegetation and environmental features of forest and range
ecosystems. Agric. Handb. 475. Washington, DC: U.S. Department of
Agriculture, Forest Service. 68 p. 
6. Johnsgard, Paul A. 1979. A guide to North American waterfowl.
Bloomington, IN: Indiana University Press. 274 p. 
7. Johnson, Douglas H.; Grier, James W. 1988. Determinants of breeding
distribution of ducks. Wildlife Monographs. 100: 1-37. 
8. Hines, J. E.; Mitchell, G. J. 1983. Gadwall nest-site selection and
nesting success. Journal of Wildlife Management. 47(4): 1063-1071.
9. 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.
10. 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. 
11. 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. 
12. Martz, Gerald F. 1967. Effects of nesting cover removal on breeding
puddle ducks. Journal of Wildlife Management. 31(2): 236-247. 
13. Musgrove, Jack W.; Musgrove, Mary R. 1943. Waterfowl in Iowa. Des
Moines, IA: State Convservation Committee. 113 p. + index. 
14. Sargeant, Alan B.; Allen, Stephen H.; Eberhardt, Robert T. 1984. Red fox
predation on breeding ducks in midcontinent North America. Wildlife
Monographs No. 89. Washington, DC: The Wildlife Society. 41 p. 
15. Schlichtemeier, Gary. 1967. Marsh burning for waterfowl. In:
Proceedings, 6th annual Tall Timbers fire ecology conference; 1967 March
6-7; Tallahassee, FL. No. 6. Tallahassee, FL: Tall Timbers Research
Station: 40-46. 
16. Sousa, Patrick J. 1985. Habitat suitability index models: gadwall
(breeding). Biological Report 82(10.100). Washington, DC: U.S.
Department of the Interior, Fish and Wildlife Service. 35 p. 
17. Springer, Paul F.; Stewart, Robert E. 1977. Gadwall nesting in Maryland.
Auk. 67: 234-235. 
18. Vermeer, Kees. 1970. Some aspects of the nesting of ducks on islands in
Lake Newell, Alberta. Journal of Wildlife Management. 34(1): 126-129.
19. DeGraaf, Richard M.; Scott, Virgil E.; Hamre, R. H.; [and others]. 1991.
Forest and rangeland birds of the United States: Natural history and
habitat use. Agric. Handb. 688. Washington, DC: U.S. Department of
Agriculture, Forest Service. 625 p. 
20. Kruse, Arnold D.; Higgins, Kenneth F. 1990. Effects of prescribed fire
upon wildlife habitat in northern mixed-grass prairie. In: Alexander, M.
E.; Bisgrove, G. F., technical coordinators. The art and science of fire
management: Proceedings, 1st Interior West Fire Council annual meeting
and workshop; 1988 October 24-27; Kananaskis Village, AB. Inf. Rep.
NOR-X-309. Edmonton, AB: Forestry Canada, Northwest Region, Northern
Forestry Centre: 182-193. 
21. Donohoe, Robert W. 1974. American hornbeam Carpinus caroliniana Walt.
In: Gill, John D.; Healy, William M., eds. Shrubs and vines for
northeastern wildlife. Gen. Tech. Rep. NE-9. Upper Darby, PA: U.S.
Department of Agriculture, Forest Service, Northeastern Forest
Experiment Station: 86-88. 
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