In the early Neolithic period, people used vessels made of stone, gyps and burnt lime. It is closely related to the European griffon vulture ("Gyps fulvus"). Griffon vultures ("Gyps fulvus") are common. "Gyps" species were the most affected by diclofenac. Population of three "Gyps" vultures in South Asia decreased by about 95% in the 1990s. It is the smallest of the "Gyps" vultures, but is still a very large bird. Recently, a fossil species "Gyps bochenskii" has been described from the late Pliocene in Bulgaria. Three of the Farman planes were christened "Aetos", "Gyps", and "Ierax". The population of the white-rumped vulture ("Gyps bengalensis") fell 99.7% between 1993 and 2002. The IUCN Red Data Book has listed "Gyps bengalensis" as "critically endangered". It is closely related to the white-backed vulture ("Gyps africanus"). Other birds include griffon vulture ("Gyps fulvus"), Egyptian vulture ("Neophron percnopterus") and horned owl. Compared to other vultures, "Gyps" species have quite feathered heads, with characteristic downy covers. "Gyps fulvus" probably on their flight over to Cres. "Gyps fulvus", "Aegypius monachus", "Aquila chrysaetos" and "Gypaetus barbatus".