LITERATURE CITED 
Bellrose, Frank C., Thomas G. Scott, Arthur S. Hawkins, Jessop B. Low. 
1961. Sex and age ratios in North American ducks. Illinois 
Natural History Survey Bulletin. vol. 27, art. 6, p. 391-474, 
Carney, Samuel M., and Aelred D. Geis. 
1960. Mallard age and sex determination from wings. Journal of 
Wildlife Management. vol. 24, no. 4, p. 372-381. 
Geis, Aelred D., and Samuel M, Carney. 
196la. Results of duck-wing collection in the Mississippi Flyway, 
1959-60. U. S. Fish and Wildlife Service, Special Scientific 
Report:Wildlife No. 54, 117 p. 
196lb. Preliminary report on the species composition and age 
ratios in duck wing collections during the 1960 hunting season. 
Ue Se Fish and Wildlife Service. Unpublished report. (filed 
Patuxent Wildlife Research Center). 25 p, =~ 
U(nited) S(tates) Fish and Wildlife Service. 
1959. Continental banding program. Unpublished report. 10 p. 
(processed). 
