On 19 October 2005, 15 Cape Vultures Gyps coprotheres were released in Namibia as part of a population supplementation programme initiated by Dr Gerhard Verdoorn and Maria Diekmann in 2002. The focus of this supplementation programme was to bolster the remaining population of Cape Vultures on the Waterberg Plateau before these few birds left the site causing the second species extinction in Namibia (the White Rhino has since been successfully reintroduced). As Cape Vultures are communal breeders, they will usually leave a breeding site altogether should the numbers of breeding birds drop below the acceptable minimum number, thereby making the breeding pair numbers insufficient for the colony to remain active. This minimum number of breeding pairs is unknown but is believed to be a flexible number dependent on the availability of breeding ledges and historical breeding numbers at different breeding sites.