sentences:  This is likely to be for protection against avian predators – in their current range, skuas, and past predators would have included the laughing owl and the New Zealand falcon.This is one of the reasons for their decline, as such nests are more vulnerable to mammalian predators.In the early 1990s, the Department of Conservation (DOC) started a captive breeding programme at Pukaha Mt Bruce Wildlife Centre, and later at Isaac Conservation and Wildlife Trust.