
of the breeding season by back-dating broods to the start of the clutch. 
Since each brood was tallied only once and there was constant intensity of 
census (100 percent) throughout the season, this method gave a better picture 
of the nesting season as regards successful nests than would a study of the 
nests themselves. 
LITERATURE CITED 
Bach, R. N. 
1952. North Dakota Water Areas. North Dakota Outdoors, April, p. 16. 
Benson, R. D. 
1948. Basic Factors in the Productivity of Waterfowl on Three Prairie 
Ponds in 1947. M.S. Thesis, University of Minnesota. 
Black, K. E., and C. D. Evans. 
1953. <A Modification of the Cannon-Projected Net Banding Trap. U.S. 
Fish and Wildlife Service, Minneapolis, Minn. 5 p. (Processed). 
Blankenship, Lytle H., C. D. Evans, M. H. Hammond, and A. S. Hawkins, 
1953. Techniques for Brood Production Studies. Mississippi Flyway 
Council Technical Committee. 14 p. (Processed). 
Bue, I. G., Lytle Blankenship, and W. H. Marshall. 
1952. The Relationship of Grazing Practices to Waterfowl Breeding Popula- 
tions and Production on Stock Ponds in Western South Dakota. Transactions, 
17th National American Wildlife Conference, p. 396-414. 
Dill, Herbert H., and William H. Thornsberry. 
1950. A Cannon-Projected Net Trap for Capturing Waterfowl. Journal of 
Wildlife Management, vol. 14, No. 2, p. 132-137. 
Engeling, Gus A. 
1950. Nesting Habits of the Mottled Duck (Anas fulvigula maculosa) in 
Colorado, Fort Bend and Brazoria Counties, Texas. M.S. Thesis, A. and M. 
College of Texas. 

Evans, Charles D. 
1951. -A Method of Color Marking Young Waterfowl. Journal of Wildlife 
Management, vol. 15, No. 1, p. 101-103. 
Evans, Charles D., Arthur S. Hawkins, and W. H. Marshall. 
1952. Movements of Waterfowl Broods in Manitoba. U. S. Fish and Wildlife 
Service, Special Scientific Report--Wildlife No. 16. 7 p. 
Hochbaum, H. Albert. 
1944. The Canvasback on a Prairie Marsh. American Wildlife Institute. 
201 p. 
Martin, A. C., Neil Hotchkill, F. M. Uhler, and W. S. Bourn. 
1953. Classification of Wetlands of the United States. U. S. Fish and 
Wildlife Service, Special Scientific Report--Wildlife No. 20. 1p. 
58 
