Project gives robin numbers a boost
The number of South Island robins in the Waimangarara bush has grown from one pair to about six couples over the last decade.
The increase was due to Kaikoura Forest and Bird's Waimangarara Restoration Project, which covered 65 hectares in Kaikoura Flat and worked to create a native forest environment for various birds over the last ten years.
The volunteers had killed more than 1300 predators, such as stoats and weasels, and encouraged the Robins to breed in the area by cultivating native Kanuka trees.
Project co-ordinator Barry Dunnett said the restoration project was a good opportunity to build a home for the robins as their numbers were in decline, particularly at their regular nesting area in the Kowhai Bush.
At least 50 per cent of their eggs were being destroyed by predators and their habitat had changed a lot due to human actions over the last couple of decades, he said.
"That's why the robins in this area have a higher success rate, we do a good job of keeping control of the predators – we knock the numbers well down."
The birds could travel up to the Mt Fyffe Bush through a thin corridor of forest provided by the Waimangarara Reserve, he said.
They did not like to fly over open spaces of more than 100 metres, which made it important to provide them with an accommodating nesting environment and the ability to travel under the [forest] canopy, he said.
"Because the robins are territorial, they benefit greatly from the predator control."
The birds preferred relatively uncovered forest-floor to allow them to rummage for food in the soil among the leaves, which meant grass and moss had to be kept to a minimum in their part of the forests.
The reserve was home to native earthworms (favoured by kiwis no longer found in the area) that grew to about 40 centimetres long, which the birds broke apart and hoarded in the forks of trees, he said.
South Island robins can lay three lots of three eggs every year, usually starting about August, which took about 18 days to hatch and the same amount of time for them to be ready to fly.
The juvenile birds are driven away from their nests after about three weeks.