54 • Wetlands: Their Use and Regulation 



The mallard, for instance, the most commonly 

 hunted waterfowl in the United States, is a dab- 

 bling duck and feeds on plants and food just under 

 the surface of the water. Bulrush, smartweed, and 

 wildrice are the emergent wedand plants, and pond- 

 weed and wild celer)' are submerged plants favored 

 by the mallard. In contrast, the canvasback, a div- 

 ing duck, typically feeds in deeper water. They pre- 

 fer submerged plants, such as pondweed, wild cel- 

 ery, and widgeon grass to emergent vegetation but 

 still may feed on emergents when preferred foods 

 are not available. Geese and swans, on the other 

 hand, favor emergent wetland vegetation to sub- 

 merged plants. Canadian and snow geese, in par- 

 ticular, feed on the rootstocks of salt marsh cord- 

 grass as well as on cultivated crops (81). 



Waterfowl also depend on wetlands for nesting 

 sites. Inland freshwater and saltwater marshes and 

 coastal tundra are the most important wedand types 

 for waterfowl breeding (96). In general, waterfowl 

 prefer wetlands where open water and vegetation 

 are interspersed. Temporarily flooded wetlands 

 have been known to have high breeding-pair densi- 

 ties, probably because of plentiful invertebrates, 

 which breeding waterfowl require for egg produc- 

 tion (96). Northern freshwater tidal marshes are 

 used to a more limited extent for breeding, and 

 wooded swamps and bottom land hardwoods are 

 used by wood ducks for nesting (66,78). 



Of the 44 species of waterfowl that use North 

 American wetlands, 4 species of geese and 10 to 



15 species of ducks are hunted in sizable numbers 

 (6,59). In the 1980-81 season, for instance, 1.9 

 million people killed 12.9 million ducks and 1.7 

 million geese (13). FWS estimated that 50 percent 

 of all hunters 16 years and older, or 5.3 million 

 hunters, hunted migratory birds (includes non- 

 waterfowl) in 1980, spending $638 million, or 11 

 percent of all hunting expenditures (32). In addi- 

 tion, FWS estimated that of 100 million Americans 



16 years and older who participated in outdoor ac- 

 tivities related to fish and wildlife, 83.2 million par- 

 ticipants spent $14.8 billion on observing and 

 photographing fish and wildlife. Sixty-six percent 

 of these participants were involved directly with 

 observing or photographing waterfowl. 



Other Birds. — There are several other types of 

 birds that are found commonly in wetlands (48). 

 The American coot is physically and ecologically 



similar to the duck and is shot in considerable 

 numbers. Coots have diets similar to those of ducks 

 but build floating nests in emergent vegetation. 

 Snipe also inhabit freshwater marshes and wet 

 meadows and are strictly carnivores, feeding on 

 aquatic invertebrates they puU from mud with their 

 long bUls. The four rail species and the gallinules, 

 which have special adaptations to wetlands, are 

 commonly found there and are hunted to some ex- 

 tent. Herons, egrets, cranes, storks, and ibises nest 

 colonially in wetlands. Herons and egrets feed on 

 fish, frog, and invertebrates in shallow marsh 

 waters. Ibises and storks nest over water in pro- 

 tected sites of deep marshes but feed in wet mead- 

 ows and uplands. 



Mammals. — A number of mammals live in wet- 

 lands. For example, muskrats may live in bank bur- 

 rows or "houses" constructed of wetland vegeta- 

 tion along the banks of freshwater and saltwater 

 marshes, rivers, and streams.'" In freshwater their 

 diets may consist of cattail, bulrushes, waterlilies, 



'"The following discussion is based on four sources of information: 

 1) Schamberger, et al. (80); 2) W. H. Burt and R. P. Grossenheider, 

 A Field Guide to the Mammals, 3d ed. (Boston: Houghton-Mifflin, 

 1976); 3) F. C. Daibner, Animals of the Tidal Marsh (New York: 

 Van Nostrand Reinhold, 1982); 4) Odum, et al. (68). 



Pholo credit: US Fishi and Wildlife Service, Jim Leupold 



A white-faced ibis tends its young in a marsh at Bear 



River National Wildlife Refuge. Many water birds 



depend on marsh vegetation for nesting sites 



