The Chatham Island black robin could become a victim of its own success unless more habitat is found

In 1980 there was only one breeding pair - now there are 445 of the birds at two Chatham Island sites.

However, there's a limit to how much food and habitat is available, with the population growing faster than the bush.

Department of Conservation's Dave Houston says the solution to continue to grow robin numbers isn't simple.

He says it's important to keep the birds in their natural environment and find another site in the Chatham Islands.