HASSELT R VAN (1960) Short contributions: On cases of bigamy or polygamy with the Pied Flycatcher Ficedula hypoleuca in the Netherlands. LIMOSA 33 (3): 204-206.

At 5 nests of the Pied Flycatcher in nestboxes on a small area (I.Yz hal in the Province of Ge1derland in 1959 never more' than two males were seen. In the opinion of the author this only can be explained by bigamy or even polygamy as reported by YON HAARTMAN (1951) for Finland

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