Wild kiwi chicks crack Auckland record
Two wild kiwi chicks discovered last week (15 January 2009) are the first to be born in the Auckland region for more than 60 years.
The baby kiwis, found at the Tawharanui Open Sanctuary, just north of Auckland, were discovered during routine monitoring by sanctuary staff and rangers.
Nervous excitement
The sanctuary runs a programme that releases kiwi back into the wild to breed.
Sanctuary coordinator Matt Maitland said he was surprised to find two extra sets of legs when he checked one of the burrows last week.
"It was one of those moments of nervous excitement," he said.
Maitland weighed the chicks, measured their bills and took a couple of feathers for DNA testing, and will now leave them to grow until the next major population count in five years' time.
Self-sustaining population
The birth of the two chicks brings the sanctuary’s new additions to at least four, but it’s believed there could be up to 10 new chicks in the 588ha sanctuary.
Over the past two years, ‘egg timer' radio transmitters have been fitted to some of the male birds before releasing them. This allows monitoring of the birds' movement from afar and gives park staff and volunteers a good indication of how the population is faring in the wild.
The sanctuary is home to another 19 untagged males whose breeding status is unknown.
"We should assume that there are more unknown chicks out there," said Maitland.
Public welcome, predators not
Tawharanui Open Sanctuary was established to recreate the conditions of an offshore island on the mainland. A predator-proof fence was installed and 44 kiwi released in 2004.
The public has year-round access to the park, and sanctuary staff say people are able to camp as kiwi "skulk about quietly at night time foraging in the bush".
Kiwi numbers
Sanctuary staff say the latest discovery means Tawharanui is now well on the way to establishing a self-sustaining kiwi population which will, in turn, help support new sites.
Kiwi in New Zealand now number around 70,000 and are split over five different species but Dr Hugh Robertson of the NZ Department of Conservation Kiwi Recovery Group says numbers are dropping overall, so operations such as Tawharanui are vital.
"I hope that this is just the start of a flourishing population behind the predator-proof fence at Tawharanui, and that we will soon be forced to look for more mainland release sites within easy reach of Auckland as this population expands rapidly," Dr Robertson said.
Prolific breeders
Kiwi are prolific breeders and usually mate for life, regularly producing huge eggs. Their eggs are one of the largest in proportion to body weight of any bird in the world.
In the Northland region of New Zealand, kiwis produce eggs at any time during the year. The incubation period is about 75 days, and it’s the male who predominantly takes on the nurturing role during this time.
When they hatch, kiwi chicks are mini-adults fully feathered and open-eyed, and after five days leave the burrow to forage for themselves. After five weeks they are ready to seek their own territory.
Vulnerable to predators
During their first three-to-four weeks, baby kiwi feed at night, and sometimes during the day, making them extremely vulnerable to predators.
Around 90 percent of kiwi chicks born in the wild die within their first six months - 70 percent of them killed by stoats and cats. Only about five percent of kiwi chicks survive to adulthood, but survivors may live into their 60s.
Kiwi habitat
Kiwi prefer lowland and coastal indigenous forest, but changes to New Zealand's original forest cover mean kiwi have to be adaptable. Today they live in many different types of vegetation, including exotic forests and rough farmland.
The size of the kiwi's territory can range from two to 100 hectares depending on the food supply of insects and berries. Males are also fiercely territorial.
The original absence of mammal predators allowed kiwi to make their homes in many different environments, from snowy tussock lands to sand dune burrows, from mossy forest floors to rough grassland.
The brown kiwi sleeps and nests in simply constructed, single-entrance burrows dug in the earth of a bank or slope. The birds use their strong legs and claws to loosen the earth, pushing it out and away from the entrance. Their daytime shelter may be in a hollow tree, under a log, in a rock crack or within a dense clump of vegetation.
More information:
Bird conservation in New Zealand
Chick and egg-timers help protect kiwis
New resolution from old idea
These topics may also be of interest to you
|
