Sydney, Aug 19 - Scientists surveying Chatham Islands, housing endangered pigeons, were pleasantly surprised to discover that the birds had recovered from the brink of extinction.

The numbers of parea, a species of endangered pigeons, had gone up to 500 from a low of 40 in the late '80s, thanks to protection of their habitat through fencing, predator control and covenanting has reversed the decline of parea.

The positive survey results could see its threat status being lowered when it is next assessed, Department of Conservation (DoC) scientific officer Ralph Powlesland said.

'The speed of recovery has been impressive. While parea will still need active protection, we're feeling a lot more positive about their long-term security,' said Powlesland.

He undertook the survey with DoC Wellington Hawke's Bay Conservancy technical support officer Lynn Adams and other New Zealand-based fauna experts Ian Flux and Peter Dilks, supported by the Chathams area office.