A large portion of the North American continental waterfowl population winters in coastal 

 Louisiana (Bellrose 1980). Because weirs influence the water levels in ponds during the winter 

 and increase the amount of aquatic vegetation, they increase the amount and quality of habitat 

 available to wintering waterfowl. Although long overlooked, the quality of the wintering habit it 

 could be extremely important to waterfowl populations (Fredrickson and Drobney 1979). The 

 quality of the wintering ground influences the health of the birds, winter survival rates, and 

 subsequent reproductive success (Heitmeyer and Fredrickson 1981; Krapu 1981; Kaminski and 

 Gluesing 1987). 



Non-game birds were more abundant in ponds influenced by weirs when free-draining ponds 

 had no water. While unmanaged ponds were draining, birds preferred these areas because food 

 was concentrated. When water conditions were similar in managed and unmanaged ponds, birds 

 used each type equally. Because numbers of non-game birds are highest in the winter, when 

 unmanaged ponds are drained much of the time, weirs improve habitat quality for many non-game 

 birds. 



Weirs have little effect on the abundance of certain mammals. Muskrats, nutrias, and swamp 

 rabbits appeared to be more abundant in areas influenced by weirs than in unweired areas, but the 

 results were not conclusive. The biggest impact weirs have on mammal numbers may be in drought 

 years when freshwater can be a limiting factor, but, because there are no data on mammal 

 populations during unusually dry years, their value to wildlife at these times is unknown. 



LITERATURE CITED 



Arthur, S.C. 1928. The fur animals of Louisiana. La. Dep. Conserv. Bull. 18. 433 pp. 



Bellrose, F.C. 1980. Ducks, geese and swans of North America. Stackpole Books, Harrisburg, 

 PA 504 pp. 



Chabreck, R.H. 1968. Weirs, plugs and artificial potholes for the management of wildlife in 

 coastal marshes. Pages 178-192 in J.D. Newsom ed. Proceedings: first coastal marsh and 

 estuary management symposium. Louisiana State University, Div. Continuing Education, Baton 

 Rouge. 



Chabreck, R.H., and CM. Hoffpauir. 1962. The use of weirs in coastal marsh management in 

 Louisiana. Proc. Annu. Conf. Southeast Game Fish Comm. 16:103-112. 



Chabreck, R.H., J.R. Love, and G. Linscombe. 1981. Foods and feeding habits of nutria in 

 brackish marsh in Louisiana. Proc. Worldwide Furbearer Conf. l(l):531-543. 



Day, J.W., Jr., R. Costanza, K. Teague, N. Taylor, G.P. Kemp, R. Day, and R.E. Becker. 1986. 

 Wetland impoundments: a global survey for comparison with the Louisiana coastal zone. La. 

 Dep. Nat. Resour., La. Geol. Surv. Div., Baton Rouge. 



Fredrickson, L.H., and R.D. Drobney. 1979. Habitat utilization by postbreeding waterfowl. Pages 

 119-131 in T. Brookhout, ed. Waterfowl and wetlands - an integrated review. Proc. 1977 S)Tnp. 

 Northcent. Sec, Wildl. Soc, Madison, WI. 152 pp. 



Heitmeyer, M.E., and L.H. Fredrickson. 1981. Do wetland conditions in the Mississippi Delta 

 hardwoods influence mallard recruitment? Trans. N. Am. Wildl. Nat. Resour. Conf. 46:44-57. 



Herke, W.H. 1971. Use of natural, and semi-impounded, Louisiana tidal marshes as nurseries 

 for fishes and crustaceans. Ph.D. Dissertation. Louisiana State University, Baton Rouge. 26-4 

 pp. 



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