Great Spotted Kiwi (Roroa)
The great spotted kiwi is classified as vunerable as it may be decreasing by as much as 43% in 3 generations (45 years). The great spotted kiwi is on the International Union for the Conservation of Nature and Natural Resources (IUCN) Red List of Threatened Species.
Great Spotted Kiwi are fiercely territorial and will aggressively defend their territory. They mark their territories with strong smelling droppings and call frequently during the night to each other and neighbouring kiwi pairs.
Great Spotted Kiwi in the Paparoa Range
The original aim of the PWT’s kiwi protection project was to trial Operation Nest Egg (BNZONE™) on great spotted kiwi to determine whether this was a viable and cost effective option for managing the species. This technique had been tried and trusted by DoC at other kiwi sites around the country with the closest being Okarito and Haast Kiwi Sanctuaries. These two sites had recently switched their efforts from intensive predator control to Operation Nest Egg as ONE provided more security for the survival of the species short term and was therefore more cost effective.
In addition to trialling BNZONE™ on great spotted kiwi/roroa the PWT had some other objectives:
- To ascertain the density, distribution and health of the great spotted kiwi/roroa population on the South Paparoa Range.
- To monitor pairs to determine breeding frequency,incubation behaviour and hatching success.
- To see if juvenile kiwi produced through BNZONE™ would go on to form breeding pairs and successfully hatch chicks of their own.
- To learn about the behaviour and ecology of these incredible and elusive kiwi.
Great Spotted Kiwi Call Sounds:
Male great spotted kiwi have a high trilling whistle repeated between 6 and 20 times and the females call is lower and harsher.
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What we did
- Between 2007 and 2009 we started comprehensive survey work to determine the general population status and where birds were most abundant, which was useful when deciding where to catch birds for monitoring.
- Next we chose two study areas to catch and monitor birds; the Croesus Basin and Mt Leitch/Watson/Roa to the south.
- Then employed contractors to catch birds and attach smart transmitters (transmitters capable of detecting start and stage of incubation).
- Between 2008 and 2014 we monitored adults and harvested more than 50 kiwi eggs from the Paparoa Range.
- 38 chicks were taken to crèche sites; 9 to Adele Island in the Abel Tasman and 29 to ‘Bois Gentil’ kiwi crèche at the base of the Paparoa Range.
- 27 birds have been released back into the Paparoa Range and we are still monitoring approximately 20 today.
What we found out
- There are still quite good numbers of adult great spotted kiwi/roroa in the Paparoa Ranges (average call rate of >4,5 calls/hour) and they are especially abundant in the upper altitudinal range of the forest where they make frequent forays along the tussock tops and rocky ridge crests.
- They are not as large as great spotted kiwi from other regions with females ranging from 2500–3200g and males ranging from 1750–2200g.
- Although generally monogamous separation does occur.
- Their territories can be very large (100ha) and range from valley floors to tussock tops where there appears to be some overlap.
- BNZONE™ is possible although the cost effectiveness of this technique for a small community group has not yet been analysed.
- Most kiwi pairs that we monitored were not successful in producing fertile eggs in consecutive years. (Out of 125 breeding attempts over seven years 59 fertile eggs were harvested and of these 46 hatched)
Out of 46 fertile eggs that hatched at Willowbank Wildlife Reserve in Christchurch, we have about 20 juvenile kiwi still alive in the wild today.
What happens next?
Now that the PWT have decided to cease doing BNZONE™ on the majority of our adult pairs, we are giving those birds a break and removing their transmitters. We will still harvest eggs from kiwi that are threatened through habitat modifications, but the focus of our kiwi monitoring is going to go back to the less invasive hands off monitoring using call count and survey techniques.
On top of this we will monitor all juveniles produced through the BNZONE™ program and released back into the Paparoa Range, long term to determine what percentage go on to form breeding pairs of their own recruiting young kiwi back into the wild. That is the ultimate way of measuring the success of the project over time.
‘To have great spotted kiwi/roroa recruitment occurring naturally in the wild at a rate that will ensure survival of the species over time’
Kiwi fact sheet from Wikipedia – Great Spotted Kiwi
Maori name: Roroa.
Scientific name: Apteryx haasti.
Relatives: ostrich, emu, cossawary, rhea, moa (extinct).
Average Lifespan: 30–40 years.
Habitat: subalpine grasslands or forests of the South Island of New Zealand.
Description: pear-shaped body, long slender bill, short strong legs, 3 powerful toes, soft hair-like charcoal grey to light brown feathers mottled with white, no visible wings.
Behaviour: flightless, nocturnal, sleeps in a burrow.
Size: 45cm tall, 2.4kg (male), 50cm tall, 3.3kg (female).
Voice: Male great spotted kiwi have a high trilling whistle repeated between 6 and 20 times and the females call is lower and harsher. Other birds that can be mistaken for kiwi especially around dusk are weka and the moreporks warm up performance of rich, deep strident ‘cree’ calls on the same note.
Senses: poor eye sight, well developed sense of smell (nostrils at tip of bill).
Diet: earthworms, grubs, beetles, cicadas, crickets, flies, spiders, caterpillars, slugs, snails, berries, seeds.
Threats: habitat loss; predators including dogs, cats, possums, and pigs.
Reproduction: pairs are monogamous. Females lay 1 egg per year which hatches after 75-85 days. The male incubates the egg during the day but the female shares the incubation during the night relieving the male for a few hours so he can feed. Within ten days of hatching the chick begins to hunt for food unaccompanied outside the burrow. Most chicks are killed by predators in the first six months of their life.
What distinguishes the Great Spotted Kiwi from the other 4 species of kiwi?
The most obvious difference is their feathers. While all 4 other species of kiwi have brown feathers in various shades, the great spotted kiwi/roroa are a dark grey-brown bird whose feathers are beautifully mottled and banded with buff and brown-black, which gives the bird its spotted appearance.
They are also said to be the largest of all kiwi species although some of the southern Tokoeka species are equally as large if not larger than great spotted kiwi.
How many Great Spotted Kiwi are there?
Before settlers arrived there were about 12 million roroa on the South Island of New Zealand. Now there are around 22,000 birds living in 3 main populations.