The Northern Harrier (Circus cyaneus / Circus hudsonius) is a medium-sized, widespread bird of prey that is known by a variety of names, such as Hen Harrier, Marsh Hawk, Blue Hawk, White-rumped Harrier, Cinereous Harrier or Frog Hawk. Female immature Northern Harrier with an eye on a pheasant hen – Nikon D500, f7.1, 1/3200, ISO 800, Nikkor 500mm VR with 1.4x TC, natural light, not baited They have not announced what taxonomic system they will be adopting. This pheasant and the others nearby could have flown away but they didn’t. Northern vs Hen Harrier With Northern Harrier being accepted by the BOURC onto Category A as a full species, what is going to happen in the light of the BOU disbanding their taxonomic sub-committee. Known for their majestic skydancing ritual, this graceful bird is one of the most threatened birds of prey in the UK. Identification of Hen Harrier (pictured here) and Northern Harrier is a major challenge, and several articles have been written on the topic from the European perspective. There were other pheasants in the area but the young female harrier only appeared to go after this hen pheasant. The hen harrier population has suffered a decline of 88 pairs (13%) over the past six years with a total UK population estimated to be 545 pairs, according to the latest figures from the fifth national hen harrier survey. T he elegant hen harrier is perhaps the most iconic bird of prey in the uplands of northern England, but it is also one of the most endangered birds in Britain. Adult males are perhaps more distinctive, with Hen Harriers being cleaner and paler.