Appendix 6.3(11) Continued 



predators (Bent 1923). Mottled ducks in general appear to be more tolerant 

 of salinity than mallards and are therefore, able to utilize a wide range 

 of marsh resources. 



Gadwall (Anas strepeva) 



According to Bateman's aerial waterfowl surveys, the gadwall is the 

 most populous duck species in the Chenier Plain, represented by an average 

 of over 600,000 birds at peak times. 



Gadwall breeding grounds are further west than those of the mallard, in 

 the western Great Plains and the lakes of the western mountains (Johnsgard 

 1975). They are not exclusively birds of the Mississippi Flyway, and may 

 travel by way of the West Coast to Mexico, or down the Central Flyway to 

 Texas and Mexico. Those traveling down the Mississippi Flyway winter in 

 Louisiana (Hawkins 1964). Gadwalls arrive in the Chenier Plain around mid- 

 October, reach peak numbers within one month and remain relatively late, 

 into April and May (Lowery 1974a). 



Gadwalls do not usually eat rice tailings. Instead they remain in fresh 

 marshes and feed upon submerged aquatic plants such as widgeongrass and pond 

 weed. They also eat seeds of marsh grasses. Smith (1973) found their diet 

 to consist of 35% Elodea densa, 33% spikerush, 22% algae and 10% assorted 

 aquatics. 



Gadwalls comprise about 9% of the average annual harvest in the six 

 county/parish area of Calcasieu, Cameron, Vermilion, Chambers, Jefferson 

 and Orange, while accounting for almost 16% of the Chenier Plain wintering 

 duck population. Reasons for underhunting appear to be twofold. The gad- 

 wall is not considered a table bird of the same caliber as the mallard by 

 many hunters, and its range on its wintering grounds is not as wide as 

 those of other species. 



American wigeon (Anas americana) 



Also known as the baldpate. This bird occurs in large numbers in the 

 Chenier Plain. It has a large breeding range that roughly coincides with 

 that of both the mallard and gadwall. The range extends northwest to the 

 Bering Sea in Alaska (Kortright 1967). Wigeons arrive in the Chenier Plain 

 in early October and remain until May. Average peak numbers are around 

 380,000 (10% of the Chenier Plain wintering waterfowl population). 



Food habits of wigeons are similar to those of the gadwall (Kortright 

 1967 and Smith 1973); it dabbles for aquatic plants and algae, and eats 

 sedge and grass seeds. It also eats wild celery and other submerged aquatic 

 plants that are brought to the surface by diving ducks. This is an interest- 

 ing specialization in food-gathering. In addition, gizzards may contain up 

 to 10% animal food that may be a result of bottom-feeding. Wigeons prefer 

 habitats similar to those of gadwalls, and like gadwalls are not common rice 

 browsers . 



92 



