Albatrosses are amongst the largest of flying birds and occupy a unique niche in the marine environment. Although they range widely from the tropics to polar seas, albatrosses occur in the windiest regions because they are specialists at soaring flight by parasitizing prevailing winds to travel rapidly over ocean basins with minimal energy expenditure. Consequently, albatrosses have the lowest flight cost of any ver­ tebrate. In general, flight costs decrease with increasing body size, with costs as lows as 1.4-2.0 x BMR reported for Wandering Albatrosses, one of the largest flying birds (10 kg). However, the specialization for soaring flight has resulted in evolutionary constraints on physiological performance for powered flight and reproductive output.