200th robin leaves the nest
200th robin leaves the nest
1 December 2005
Auckland Regional Council is celebrating the success of the North Island robin reintroduction project at Wenderholm Regional Park, with the fledging of the 200th chick this week.
ARC Natural Heritage Scientist Tim Lovegrove says that in March 1999, 21 birds were transferred from Tiritiri Matangi Island to Wenderholm Regional Park.
“On Tiri many of the robins were living only in about 15 hectares of the older forest and when this area became fully occupied, significant numbers of young robins were dying each winter because of a lack of suitable habitat. This made it possible for us to harvest some of these surplus birds for the transfer to Wenderholm.
“Over the past seven seasons at Wenderholm, between 20 to 40 young have been produced each year from the resident pairs of robins, and this season, the 200th chick has fledged.”
Tim Lovegrove says one of the main reasons robins were chosen for the first bird reintroduction at Wenderholm is because they are easy to catch, transfer and monitor.
“Robins are very tame and although they are locally extinct, they can still survive in environments with some introduced pests and are generally a little more hardy than some other native birds.
“It has also been an excellent opportunity to compare survival and breeding success with other robin releases elsewhere in the North Island. We have found that survival has compared well with the other sites and the Wenderholm robins have produced more young per pair.
“There is a high rate of dispersal of young robins from Wenderholm. We have found some of our young birds as far a field as Moirs Hill near Warkworth and in several bush blocks on private land west of Waiwera and Puhoi.”
Mr Lovegrove says Wenderholm was the ideal place for the robin release because of its ongoing intensive pest control.
“There are around 250 poison bait stations to control rats and possums and because Wenderholm is located on a peninsula, this already slows down the rate of reinvasion by animal pests.”
ARC Parks and Heritage Committee Deputy Chair Christine Rose says ARC staff and volunteers are to be commended for the success of the programme.
“It’s excellent to see the robin breeding programme has taken off so successfully. Because the results have been so positive, this now provides an opportunity to reintroduce other bird species.
“Without the help of volunteers who have given up their time and assisted with the programme, we might not have been celebrating the 200th chick about to fledge.”
Cr Rose says people can also enhance the robins’ chances of survival by controlling predators on their own properties, including trapping possums and rats.
“Many local farmers are already actively contributing to Rodney’s biosecurity and biodiversity goals by pest control on their properties in the area where the robins have spread.”
- Tiritiri Matangi was a good source of birds for the transfer because research by Doug Armstrong and his Massey University research students showed that the population of 30 to 40 pairs of robins on the island produces a large surplus of young each year. Harvesting some of these surplus birds for releases at new sites means that fewer young robins die of starvation on Tiritiri Matangi during the winter.
- Robins also still occur on the mainland in the North Island on the Volcanic Plateau. Their continued survival there in the face of a range of introduced predatory mammals, such as rats, cats and stoats shows that robin populations can withstand a certain level of predation pressure.
The control programme has been running continuously since 1993, and was begun after a study by former DSIR scientist Mick Clout showed that native pigeons or kereru were failing to produce any young at all as a result of nest predation by rats and possums. The kereru are now nesting successfully, and so too are the tui. Wenderholm supports healthy populations of these species, which in turn boost the numbers of these birds in the surrounding district.