The White Tailed Swallow was first introduced to science in 1942 when C. W. Bensoii reported it in southern Ethiopia from Yabello to Mega in short grass savanna with small acacia thorn bush. This endemic, related to the Pied Winged Swallow (Hirundo Leucosoma) of western Africa and the Pearl Breasted Swallow (H. diniidiata) of southern Africa, is common but restricted to an area of about 4850 square kilometers (3000 square miles) between 1200 and 1350 meters (4000 – 4500 feet). This restriction has baffled scientists because there is no obvious explanation, particularly no natural barriers or boundaries which mark off the area, for such a limited distribution. In recent years there have been reports of the swallow in the Addis Ababa area. Studies of this species in the future may show that its distribution is not as limited as thought. The species is unique among swallows in having the greater part of the tail white; the white is very conspicuous in flight. The White Tailed Swallow is thought to be a sedentary species, remaining mainly in its home range. It is not associated with human habitation. C. W. Benson suggested that this swallow may build its nest in January and February in holes in the tail chimney shaped ant hills common in the area. The nest, however, has not been discovered.