APPENDIX 6.3 CHENIER PLAIN BIOLOGICAL DATA 

 Appendix 6.3(1). Waterfowl sampling techniques and procedures. 



Permanent north-south aerial transect lines were established at approxi- 

 mately 7-1/2 mile intervals across the Chenier Plain in 1968. A fixed wing 

 aircraft was used to fly these lines and to examine a belt transect 1/8 mile 

 each side of the aircraft. Ducks and coots were recorded by species and by 

 habitat type. An elevation of 100 to 150 feet was maintained while conduct- 

 ing the surveys. 



Since the aircraft was not equipped with amphibious landing gear a 

 greater (safer) altitude was maintained over large bodies of water. Within 

 the Chenier Plain, Sabine, Calcasieu, Grand and White Lakes were thus ex- 

 cluded from the survey. While diving ducks, principally lesser scaup, were 

 known to be present on these lakes no effort was made to count them because 

 of the unreliability of counts that were conducted at the higher altitude. 

 Birds were difficult to see under conditions of ideal visibility, and became 

 almost impossible to see when the waters were choppy. 



Geese were not recorded during these low level waterfowl inventory 

 flights. The extreme flushing distance of geese made it impossible to deter- 

 mine what portion of the airborne flocks were flushed from the survey strip. 

 Some goose inventory data were available for southwest Louisiana (U.S. Soil 

 Conservation Service 1974) . 



Birds were recorded by five habitat types: Agriculture, Salt Marsh, 

 Brackish Marsh, Intermediate Marsh and Fresh Marsh. Survey records did not 

 delineate bird distribution by land use categories within the Agriculture 

 Habitat type. Bateman (1977 per comm.) stated that as a general rule about 

 75% of the ducks and 60% of the geese found in the Agriculture Habitat type 

 were in rice fields. 



One additional judgment was necessary to utilize the survey information 

 from the agriculture habitat. Since transects ran from the Gulf to U.S. High- 

 way 90 many of the birds recorded in the Agriculture Habitat were between the 

 northern boundary of the Chenier Plain and U.S. Highway 90. After carefully 

 examining topographic maps, Bateman suggested that 80% of the ducks, 80% of 

 the coots, and 60% of the geese inventoried in the Agriculture Habitat should 

 be assigned to the Chenier Plain. 



Since the Inland Open Water Habitat was not specifically inventoried, we 

 were unable to use these aerial surveys to estimate waterfowl use. The great- 

 est acreage in this habitat type is in the four large lakes excluded from the 

 surveys for safety reasons. The ducks using water bodies 10 acres in size 

 but smaller than these lakes were included in the count of the adjacent habi- 

 tat type. 



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