Cory’s Bittern, Ixobrychusneoxenusexilis: morph, mutant, or mixed bag?

Authors

  • Paul Smith Fauna Paraguay, Encarnación, Departamento Itapúa, Paraguay and Para La Tierra, Reserva Natural Laguna Blanca, Municipalidad de Santa Barbara, Departamento San Pedro

DOI:

https://doi.org/10.22621/cfn.v128i4.1628

Keywords:

Cory’s Bittern, Ixobrychus neoxenus, Ardetta neoxena, Least Bittern, Ixobrychus exilis, leucism, melanism, Ontario, Florida

Abstract

Cory’s Bittern (Ixobrychusneoxenusexilis) is an enigmatic form, usually referred to as a rare dark colour phase or morph of Least Bittern (Ixobrychus exilis [Gmelin, 1789]). A review of the literature indicates that birds identified as Cory’s Bittern show considerable plumage variation and commonly exhibit multiple plumage anomalies. Temporal and spatial clumping of records shows that they are of irregular occurrence; thus, they do not meet the criteria for recognition as a colour morph. Cory’s Bittern should thus be viewed as a colloquial name that refers to any one of a number of abnormally dark-plumaged, genetically undefined and phenotypically heterogeneous Least Bitterns.

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Published

2015-01-29

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Section

Articles