Table 25. The percent of the area of ponds and lakes covered with 

 submerged vegetation in August, 1968 (Chabreck 1971a). 



ponds (Bell rose 1930) and in this case are 

 associated with marsh habitats. 



Compared to ducks, much less inforna- 

 tion is available about wading bird ecolo- 

 gy in delta marshes. This is surprising 

 when it is considered that they are abun- 

 dant year-round residents. The herons and 

 egrets (Table 27) are mostly carnivorous, 

 catching frogs, small fish, snakes, craw- 

 fish, and a wide assortinent of wornis and 

 insects (Mabie 1976). They prefer to fish 

 in very shallow marsh ponds and along the 

 bayous that drain marshes. They also 

 nest in marshes or in close-by mangrove 

 thickets, wax myrtles, and uplands. 

 They appear to prefer the brackish marsh 

 zone for feeding. Densities range up to 

 100 or more per 100 ha, and average from 

 6 to 25 per 100 ha (Sasser et al . 1982). 

 A number of heronries occur in the delta 

 marshes (Portnoy 1977). They are aban- 

 doned and refonned in other places fairly 

 frequently. For example, of 27 sites 

 identified by Portnoy (1977) in the 

 Barataria basin only 17 were active in 

 1932, and at least 4 new nesting colonies 

 were found (Sasser et al. 1982). It would 

 be interesting to know whether the nesting 

 of wading birds in a congested area made 

 much impact on the local nutrient cycles. 

 Certainly this has been shown for other 

 birds, especially where huge guano 

 deposits have resulted (Deevey 1970). 



Rails (Rail us spp.), the seaside 

 sparrow (Ain;nospiza maritima ) , the great- 



Table 27. Density of wading birds and 

 pelicans (number/100 ha) by marsh zone, in 

 the Barataria basin, 1980-81 (total for 6 

 fl ights; Sasser et al. 1982). 



^Total number of ducks/6 flights/100 ha. 

 Total density divided by number of survey 

 fl ights. 



70 



