THE Mute Swan (Cygnus olor) is a monogamous species, and menage a trois appears to be of uncommon occurrence. The term--menage a trois--was borrowed by F. B. Kirkman from human affairs and applied to the association of three individuals of a bird-species for the purpose of nesting. As a label, menage a trois is preferred to its synonym, bigamy, because menage a trois implies the setting-up of an ...

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