Aotea’s Lizards, Bats and invertebrates
Niho taniwha
Chevron skink
Oligosoma homalonotum
Aotea, Great Barrier Island is home to 13 species of lizards (5 gecko and 8 skinks). The “Teeth of the Taniwha” or Chevron Skink was the stuff of myth and legends from when it was first described in 1906 until the 1970s.
Special Fact! The chevron skink is one of New Zealand’s rarest and most secretive lizards. They are currently only known to be found on Great Barrier Island / Aotea and Te Hauturu-o-Toi / Little Barrier Island in the Hauraki Gulf. Maori know the chevron skink as ‘Niho Taniwha’ meaning ‘teeth of the Taniwha’ in reference to the very distinctive v shaped markings on it’s back. These chevron like patterns also give the lizard its common name. Our largest skink has a life span of 20+years, terrestrial and arboreal, run and freeze anti-predator behaviour. Chevron skinks are capable of making noises and will often grunt or squeak on being disturbed.
Lifecyle: Female chevron skinks give birth to live young in mid to late summer, and can have up to 8 at once. It is not known if chevron skinks breed every year.
Features: Dark bands extend down the face of the chevron skink from below the eye to just under the lower lip. Between these two bands is a distinctive pale coloured “teardrop” shape. These patterns are unique to each chevron skink and can be used to identify individuals.
Feeding: Invertebrates.
Threats: Habitat modification, introduced predatory pests such as rats and cats
predators (including domestic cats),
residential areas and vehicles.
Size: length of 30+ cms.
Status: Barrier islands endemic.
Threatened: Nationally vulnerable.
Where: Forests, riparian edges and streams. Chevron skinks are good climbers and have been shown to climb trees during periods of heavy rain to avoid flooding in the streams and creeks in which they live.
Photo credit: Windy Hill Sanctuary Collection
Duvaucel's gecko
Hoplodactylus duvaucelii
Special fact! NZ’s largest living gecko species. Growing up to 30 cm in length and weighing up to 120 grams, New Zealand’s largest lizard is also amongst the world’s largest geckos. They live in the forest and are mostly nocturnal, feeding on insects.
Features: Life span of 35+ years. Robust species with a thick head, large trunk and tail. The back is olive brown to olive green with pale and irregular crossbar shaped splotches down the back, usually from the nape of the neck to the base of the tail. The underside is paler than the back, usually a pale uniform grey but can be softly blotched. Duvaucel’s gecko have a pink mouth and tongue. The forehead is slightly concave with yellow eyes and large oval openings for the ears.
Feeding: Large invertebrates (moths and weta), fruit and nectar. The diet of Duvaucel’s gecko is largely insectivorous, however, they will also eat plant material, nectar, and fruit. There are records of Duvaucel’s gecko predating upon other lizards and the eggs of shearwaters.
Breeding: Duvaucel’s gecko give birth to 1-2 live young and have a low annual reproductive output. Gestation has been variously reported as between 5 months to longer than a year. Individuals become sexually mature at about 7 years old.
Threats: Habitat loss and introduced predators.
Size: 300mm length and 120g weight.
Status: New Zealand endemic.
At risk: Relict.
Where: Forest, scrub, cliffs, bluffs and coastlines. A largely nocturnal species, Duvaucel’s gecko can remain active at low temperatures but actively regulate their body temperature by sun basking. During the day they tend to hide in tree hollows, under logs, stones or bark, rock crevices or petrel burrows.
Photo credit: Dylan van Winkel & J Wairepo
Pekapeka / Long-tailed bat
Chalinolobus tuberculate
Special fact! They can fly up to 60 kmh. The long-tailed bat is classed as ‘nationally critical’ the highest threat ranking there can be. They are in danger of extinction in the medium term if nothing is done to reverse their population declines. These species are a high priority for conservation. Maori folklore refer to bats as pekapeka and associate them with the mythical, night-flying bird, hokioi, which foretells death or disaster.
Features: Long-tailed bats are smaller than the short-tailed bat, chestnut brown in colour, have small ears and weigh 8-11 grams. Low frequency echolocation 40khz, life span of 20+ years. They fly at dusk along forest edges.
Feeding: Hawking (capturing aerial insects).
Mating: February – March, they are believed to produce only one offspring each year. December – January, roosts in cavities and loose bark of large canopy trees in groups of up to 120 female bats.
Threats: Introduced mammalian predators, domestic animals, habitat destruction through logging and clearance of lowland forest.
Status: New Zealand endemic.
Threatened: Nationally vulnerable.
Where: Native and plantation forests.
Photo credit: ColinO'Donnell & gerald Kelly
Freshwater Crayfish / Kōura
Special Facts! Kōura need oxygen like all living animals and plants which they get from the water through their gills, under the thorax where the legs join the body. Water is sucked in, pumped forwards over the gills and out through the mouth. If the gills get clogged they can back-pump to flush out any debris
Features: They are dark green and mottled, often their waving feelers and black beady eyes are all that can be seen.
Reproduction: Female kōura produce eggs between April and December, and most in May and June. She carries the berry-like eggs, between 20 to 200, under the side flaps of her abdomen, when she is said to be ‘in berry’. Small kōura hatch about 3 to 4 months later, looking exactly like their parents in miniature. They cling to their mothers with their pincers until they are nearly 4 mm long, around December of their first year. By their fourth year they are 20 mm long and become adults.
Feeding: Kōura is a scavenger that feeds on leftovers that float by in the water or settle on the bottom; old leaves, small insects are favourites. It does not go hunting for its food. Once food is caught in the pincers it is torn up, pushed into its mouth to be ground up and separated by a filter system that lets only fine pieces pass through to the small stomach to be digested.
Threats: Habitat degradation, predation from introduced species, over fishing
Status: Threatened
Where: The live in fresh water such as streams, lakes and ponds, and even in swamps. Kōura shelter between stones on gravelly bottoms but they can burrow into muddy bottoms, and will burrow well down into swamps that dry out over summer, to wait until the water returns
Photo credit: Windy Hill Sanctuary Collection
Hochstetter’s frog
Leiopelma hochstetteri
Special fact! Only NZ native frog to have a tadpole stage. It is the most aquatic of the native frogs (living beside streams), is generally dark brown, grows up to 48 mm long, has partially webbed feet and has more warts than the other native frogs.
Features: Semi-aquatic, partially webbed toes, life span of 30-40 years, 4-22 eggs.
Threats: Habitat destruction by agriculture, forestry, sub-division and pigs causing stream siltation, rats, cats, diseases from introduced frogs.
Size: Males to 38mm and females to 50mm.
Status: New Zealand endemic.
At risk: Declining.
Where: Riparian edges and streams, native and plantation forests.
Photo credit: Windy Hill Sanctuary Collection
Velvet worm peripatus
Peripatoides sp.
Special fact! Known as ‘living fossils’ they have not changed for 500 million years. They look a bit like caterpillars and have pairs of stumpy legs along the length of their body.
Features: Cautious and slow-moving.
Feeding: Shoot out jets of sticky fluid to trap insects.
Breeding: Live births. They are believed to live for about 5 years and the females can produce 10–20 offspring each year. Some species lay eggs, but most hatch them internally and bear live young.
Threats: Habitat loss, increased dry periods caused by climate change, collectors, diseases, rats, pigs and cats.
Size: 5-20mm.
Status: New Zealand endemic.
At risk: Data deficient.
Where: Damp environments with logs and leaf litter. They are found in most forested parts of New Zealand, but also linger in remnant patches, scrub and gardens. They are also occasionally found in pasture, alpine and city park sites. The velvety skin of peripatus has permanently open pores, which means that they can easily dry out. Consequently, they are mostly found in shady, cool and damp areas. They hide deep within rotting logs and under leaves and debris during the day, venturing out at night to prey on other invertebrates, which they catch with jets of sticky fluid.
Photo credit: Windy Hill Sanctuary Collection
Paua slug / Land snail family: Rhytididae
Schizoglossa novoseelandica barrierensis
Features: Land slug, vestigial shell (not used). These carnivorous slugs are found only in the North Island of NZ and have a distinctive paua shaped shell on their back
Feeding: Predatory carnivore.
Breeding: Eggs with a calcareous surface.
Threats: Introduced pigs and rats, birds and habitat destruction.
Size: 20mm long, 13mm wide and 6mm high.
Status: Aotea endemic.
At risk: Data deficient.
Where: Native broadleaf and coastal forests.
Photo credit Windy Hill Sanctuary Collection
WĒTĀ
Special Fact! Wētā have been around for hundreds of millions of years – with fossils dating back before some Dinosaurs. There are over 100 species, which can be categorised into 5 different groups: Tree wētā, Ground wētā, Cave wētā, Giant wētā and Tusked wētā. Here on Aotea we do not have the Tusked and Giant wētā. However they can be found on neighbouring pest-free islands in the Hauraki Gulf. Wētā are endemic to New Zealand and can range from a tiny 7 grams all the way up to 35 grams – that’s heavier than a Sparrow!
Features: A flightless cricket relative with spiny legs, large tusks and hard exterior.
Feeding: Predominantly herbivorous and sometimes other insects.
Breeding: Females have long ovipositors that look like stingers to lay their eggs.
Threats: Introduced predators such as rats, hedgehogs and cats. Along with modification of their habitat by humans and grazing animals.
Size: Between 7-35 grams.
Status: Endemic
At risk: Varying risk levels with many being threatened or endangered
Where: A variety of habitats from forests, under logs and rocks, grasslands, caves, trees and scrubland.
Photo Credit: Windy Hill Sanctuary Collection
Information source www.doc.govt.nz