Pardannelse hos gråanden.
By: Tegninger: Preben Gross.
Series: Natur og museum ;; 14. årg., nr. 4
Publisher: Naturhistorisk Museum
Published: 1971
Place of publication: Århus
Language: dan
Number of pages: 22
Subjects: Mallard.; Birds -- Behavior.
Notes: Bibliography: p. 22.
Cover title.