through November and peak in mid-December. There 

 is some evidence that a segment of the green-winged 

 teal population migrates farther southward, causing 

 population declines in late December and January. 

 By February, the trans-Gulf migrants begin returning 

 to the Chenier Plain from the south, and populations 

 temporarily increase. However, other birds begin the 

 northward migration by mid-February and populations 

 decline again (Smith 1961). 



The green-winged teal is one of the smallest North 

 American waterfowl. Preferred feeding habitats are 

 large open flats of 5 to 10 ha (12 to 25 a), with water 

 less than 10 cm (4 in) deep. Habitats include fresh to 

 brackish marshes, but large flocks are frequently found 

 in rice fields. Green-winged teal move from daytime 

 resting areas at dusk to feeding areas, and return to the 

 resting areas at dawn (Tamisier 1976). 



This duck often concentrates in great flocks, at 

 times exceeding 100,000 birds (Smith 1961). Prior to 

 implementation of the Federal point system for duck 

 shooting, the green-wing was seldom shot because 

 hunters preferred bigger ducks; however, the point sys- 

 tem probably placed greater hunting pressure on the 

 green-winged teal than on any other species in the Che- 

 nier Plain. 



Seeds of annual plants are favorite foods. The bird 

 will often feed heavily on plants with very small seeds 

 such as spikerush and waterhemp. 



The green-winged teal does not breed on the Che- 

 nier Plain. The species migrates northward in the spring 

 to breeding areas in the Dakotas, Minnesota, and the 

 prairie region of Canada and Alaska. 



5.3.45 BLUE-WINGED TEAL {Anas discors) 



Before 1957, the blue-winged teal was largely a 

 transient in the Chenier Plain and large concentrations 

 were present only in the fall and spring while birds 

 were migrating. However, marsh changes associated 

 with Hurricane Audrey in June 1957 and an extremely 

 high nutria population that competed for the available 

 food supply altered the migration patterns of the blue- 

 wing. For several years, a large portion of the popula- 

 tion remained throughout the winter on the Chenier 

 Plain (Smith 1961). This pattern continued for several 

 years and was reinforced by high production of annual 

 plant growth during prolonged summer droughts dur- 

 ing the early 1960's. Since then, the migration pattern 

 has reverted largely to that followed prior to 1957. 

 The departure of the blue-winged teal to more southerly 

 wintering areas during the fall and their return in the 

 spring meant that a major segment of the population 

 was absent during the winter season. 



Habitat preferences of the blue-winged teal closely 

 parallel those of the green-winged teal. Migrants that 

 begin arriving on the Chenier Plain in late August use 

 mainly fresh to brackish marshes and feed on the leaves 

 and seeds of aquatic plants and associated invertebrates. 

 Blue-wings also use areas where seeds from early crops 

 of annual plants are available and water depths are 

 favorable. Shallow ponds in brackish marshes, which 



dry up in early summer and produce dense stands of 

 marsh purselane, are a favorite late summer habitat. 

 Birds continue to use such areas until they migrate to 

 tropical wintering areas. 



Late winter habitats are fresh and intermediate 

 marshes and rice fields with preferred water depths less 

 than 20 cm (8 in). The marshes contain an abundance 

 of seeds of annual plants from the previous growing 

 season (Chabreck 1978). 



The diet of blue-winged teal in one study was 

 mostly insects and moUusks, whereas rice composed 

 almost 60% of the blue-wings' diet in Texas (Bennet 

 1938). Kimble (1958) examined the gizzards of blue- 

 winged teal from Cameron Parish and found that seeds 

 made up over 75% of the contents, mostly from saw- 

 grass and California bulrush. The seeds and leaves of 

 widgeongrass made up almost one-fourth of the food 

 items and consisted of seeds and leafy material in 

 about equal amounts. Animal matter made up less than 

 1% of the gizzard contents. 



Although the major nesting area of blue-winged 

 teal is the prairie region of the north central states and 

 south central Canada, a small segment of the popula- 

 tion nests in the Chenier Plain (Lowery 1974a). The 

 number of resident breeders is usually very low, and 

 most people are not aware of the birds' presence. In 

 some years, such as 1958, large numbers remained 

 and nesting blue-wings or broods were conspicuous 

 (Lynch 1967). 



Most nesting takes place in early spring, when 8 

 to 12 eggs are laid in down-hned nests of grasses and 

 reeds on the margin of ponds and sloughs (Lowery 

 1974a). Some nests are constructed on cheniers and 

 pastures considerable distances from water. 



5.3.46 NORTHERN SHOVELER (Anas clypeata) 



Shovelers migrate into the Chenier Plain in mid- 

 September and substantial numbers are present by 

 mid-October. Many of the birds make only brief stop- 

 overs before continuing to move to southerly wintering 

 areas. Concentrations do not usually peak until March 

 when migrants returning from the south join those 

 flocks which overwintered on the Chenier Plain. Many 

 birds remain until mid-April and some remain well into 

 May before migrating northward (Smith 1961). 



Although the greatest concentrations of shovelers 

 are found in freshwater and brackish ponds, some 

 occupy areas of higher salinity than most other dabbl- 

 ing ducks(Smith 1961). Preferred habitat, regardless of 

 water salinity, consists of marsh interspersed with open 

 water less than 10 cm (4 in) deep (Chabreck 1978). 



Shovelers are relatively small ducks with a spatu- 

 late bill with comb-like lamellae around the perimeter, 

 which are used to strain food from water (Johnsgard 

 1975). Shovelers tend to prefer shallow, turbid water 

 and feed mostly on small crustaceans, which comprise 

 about 30% to 40% of their diet. Favored plants are 

 pondweed, vegetative parts of bulrush and other 

 rushes, and sometimes even rice (Smith 1973). 



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