Weidraan, U. 1958. Verhalensstudien an Stockende ( Anas platyrhynchos L.). II, 

 Versuch zur Auslosung und Pragung der Nachfogel und Anschlussreaktion. 

 Z. Tierpsychol. 15: 277-300. [In German with English summary.] 



1957 



Atwood, E. L. 1957. Mallard breeding range density index map. U.S. Fish & 

 Wildl. Serv. 2 pp. 



Beter, R. A. 1957. A comparative winter food habit study of dabbling ducks 

 from the brackish Lake Borgne Marsh of St. Bernard Parish and the fresh 

 marsh of Pass a Loutre (Miss. Delta) Plaquemines Parish, Louisiana. M.S. 

 thesis, La. St. Univ. /Baton Rouge, LA. viii and 73 pp. 



Boyd, H. 1957. Early sexual maturity of a female Mallard. Brit. Birds 50: 

 302-303. 



Dzubin, A. 1957. Pairing display and spring and summer flights of the Mal- 

 lard. Blue Jay 15: 10-13. 



Eygenraam, J. A. 1957. The sex-ratio and the production of the Mallard, Anas 

 platyrhynchos L. Ardea 45: 117-143. 



Peters, S. S. 1957. Brood capture involving conflict between two female Mal- 

 lards. Wilson Bull. 69: 363-364. 



Winner, R. W. 1957. A study of local and migratory movements of Black and 



Mallard duck populations in central Ohio. Ph.D. thesis, Ohio St. Univ./ 

 Columbus , OH. 



1956 



Goodwin, C. E. 1956. Black Duck and Mallard populations in the Toronto area. 

 Ont. Field Biol. 10: 7-18. 



Hickey, J. J. 1956. Autumnal migration of ducks banded in eastern Wisconsin. 

 Trans. Wise. Acad. Sci . , Arts, Letters 45: 59-76. 



Koskimies, J. 1956. [The age of the Mallard.] Suomen Riista 10: 102-104. 

 [In Finnish with English summary.] 



Larionov, V. F. 1956. Changes in the term of breeding season in the Mallard. 

 Zool. Zh. 31: 89-95. [In Russian with English summary.] 



Lebret, T. 1956. De Wilde Eend , Anas platyrhynchos L. als Nederlandse Stand- 

 vogel. Ardea 44: 281-283. [In Dutch with English summary.] 



Weidmann, U. 1956. Verhaltensstudien an der Stockente ( Anas platyrhynchos L.) 

 I. Das Aktionssystem. Z. Tierpsychol. 13: 208-271. [In German.] 



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