Guidelines for assigning species rank


  • This paper is an official document of the British Ornithologists’ Union.

  • The British Ornithologists’ Union wishes to express its gratitude to the late Dr P. A. Clancey for a bequest which, among other things, has facilitated the publication of this paper.

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Developments in several fields of study (including bio-acoustics and the analysis of DNA) together with reappraisals of the nature of species have impacted significantly on avian taxonomy. The BOU's Taxonomic Subcommittee has developed guidelines for the application of species limits to sympatric, parapatric, allopatric and hybridizing taxa. These are published here to assist researchers understand the rationale behind the committee's taxonomic recommendations relating to the British List.