Appendix 6.3(11) Continued 



ducks by their long necks and stout legs, and are actually closer in 

 phylogeny to geese than ducks. 



Fulvous tree ducks appear to favor seeds and grains, such as Eohinoohloa 

 and rice, but are adept at both diving and dabbling (Johnsgard 1975). 



Redhead (Ay thy a amevioana) 



Although common in coastal marshes of south Texas and the Chandeleur 

 Islands off the Louisiana coast, the redhead duck is rare in the Chenier 

 Plain. This diving duck is commonly found along parts of the Gulf coast 

 between November and February. Evidence suggests the species is declining 

 in numbers (Louisiana Wildlife and Fisheries Commission 1961). 



Canvasback (Ay thy a valisinevia) 



The canvasback is the largest of diving ducks, and is popular with 

 hunters. The species is rare in the Chenier Plain, and populations are de- 

 clining (Louisiana Wildlife and Fisheries Commission 1961). The canvasback 

 feeds primarily of wild celery and other aquatic plants. 



American coot (Fuliaa amevioana) 



American coots are ducklike members of the rail family, and resemble 

 their relatives in most biological respects, although they are easily con- 

 fused with some diving ducks by the uninitiated bird watcher. Coots prefer 

 freshwater marshes where they feed on aquatic plants. They migrate from 

 their breeding grounds across northern North America in early September, 

 and are common in the Chenier Plain until late spring. Some have been known 

 to nest in the Chenier Plain. They winter in large numbers here, but are 

 not considered a desirable game bird. They are poor flyers and require long 

 distances to become airborne. 



Methodology and Applications 



Much of the quantitative analyses of waterfowl population dynamics 

 were adopted from the Louisiana periodic Waterfowl Inventory, an aerial sur- 

 vey conducted by Hugh A. Bateman, Jr. , waterfowl biologist with the Louisi- 

 ana Wildlife and Fisheries Commission. This survey is a continuation of 

 aerial surveys initiated by Richard K. Yancey in 1949. The present survey 

 is more statistically sound, from a sampling viewpoint, than previous 

 waterfowl counts in Louisiana. 



Since September 1969, the survey has been conducted with a Cessna air- 

 craft, with observer and pilot, each counting birds on their respective 

 sides of the plane. The plane is flown at an altitude of approximately 200 

 ft. Birds on large open water bodies are not counted, since the aircraft 

 must fly at altitudes of 900 ft over these situations for safety reasons. 



Transects follow longitudinal lines at 7.5' intervals with termini at 

 U.S. Highway 90 in the north, and the Gulf coast line in the south. From 

 Marsh Island east, the transect interval is increased to 15' of longitude, 

 because of the subsequently great increase in average transect length. 



96 



