Abstract

The Hen Harrier Circus c. cyaneus and Northern Harrier C. cyaneus hudsonius are classified as conspecifics by some modern authors and as separate species by others. The tendency to treat the two as conspecifics may have its origin in erroneous nineteenth-century illustrations, and their allopatry has meant that twentieth-century adherence to the Biological Species Concept has hindered attempts to classify them to universal approval. This dichotomy of opinion is a hindrance to our understanding of both harriers, and may adversely affect their conservation.