Dogs threaten kiwi survival
5 October 2005
Dogs threaten kiwi survival
Kiwi eggs are hatching thick and fast at Auckland Zoo, but staff are concerned about depredation once the kiwi are released.
Auckland Zoo’s native fauna team leader, Andrew Nelson, says that the problem is caused by dogs. “Our breeding success is in danger of being snuffed out by out-of-control domestic dogs,” says Mr Nelson.
The zoo, on average, has a 93 per cent success rate with the incubating, hatching, rearing and releasing of kiwi. This is part of the Bank of New Zealand Kiwi Recovery Trust's Operation Nest Egg Programme – a programme run in partnership with the Department of Conservation (DOC). To date, the zoo, which receives between 18 to 20 eggs each season, has successfully released 122 kiwi for the programme.
"In Northland areas without predator control, the kiwi population is declining by 4 per cent annually, and halving every 18 years," says DOC National Kiwi Co-ordinator, Research & Monitoring, Hugh Robertson. "But in areas that are intensively trapped, we're seeing an 18 per cent per annum increase in kiwi numbers, so we've got 20 per cent of all eggs laid resulting in adult kiwi."
Both north west Whangarei and Bream Head are intensively trapped, and DOC has received some great community support, with locals also trapping large areas around the reserves, creating a buffer, and reducing the chances of re-invasion by predators," says DOC Whangarei kiwi ranger, Sue Bell. “We’ve sorted out how to increase chick survivorship through trapping their predators, but we still seem to be losing when it comes to educating people about their dogs.”
The North Island brown kiwi population currently stands at 25,000, but is at risk.
“There is still hope for the kiwi, and hundreds of dedicated people are working across the country to help kiwi populations recover and thrive,” says Bank of New Zealand Kiwi Recovery Trust Chief Executive, Michelle Impey. “However, we need all New Zealanders to take the current situation with our national icon seriously in order to prevent predictions that kiwi will become extinct in some mainland areas within 15 years.”
Because 95 per cent of kiwi chicks are killed by predators in their first six months, DOC collects eggs from several areas northwest of Whangarei. Auckland Zoo's Native Fauna team incubates, hatches and rears these chicks. On regaining their birth weight (around 3 weeks), they are transferred to the kiwi creche and predator-free island, Motuora. Once they reach 1kg in weight, these kiwi are then released back to DOC's mainland Northland reserve at Bream Head.
"The birds we have released at Bream Head appear to be doing really well, and we're still monitoring birds that were part of the first release in 2001, who are now breeding. In managed areas throughout Northland, we have a 62 pre cent chick survival rate," says Ms Bell.
"It’s a great achievement, but like our conservation partners, we're really concerned that this good work is at risk because there are some dog owners in Northland who are just not being responsible,” says Mr Nelson. “As a result, too many kiwi are still being killed by dogs.
"Keeping your dog on a lead, and knowing where your dog is at all times is an absolute must," says Ms Bell. In mid-August, two female kiwis, one of which was carrying an egg, were killed by dogs running loose in the Bream Head reserve. "It's a classic example of kiwi deaths that could have been avoided."
She also says that kiwi in Northland have a life expectancy of just 13 years, compared to 40 to 50 years in other areas, and that Northland’s dog problem is a significant contributor to this shortened life expectancy.