Maud Island Frog (Leiopelma Pakeka)

These frogs are relatively large (also up to 50mm long), and are generally dark brown.  Until recently, they were only found on Maud Island in the Marlborough Sounds; however, some L. Pakeka have been translocated to several other predator-free islands in the Marlborough Sounds. The latest estimate of the number of individuals of this species is around 40,000.
They are nocturnal and catch their prey by grabbing it with their mouth as they do not flick their tongues out like many other frogs. Although these frogs have never been observed breeding in the wild, Dr Ben Bell of Victoria University has made some observations from an outdoor enclosure. He discovered that in captivity frogs lay 1-19 eggs in December in moist depressions under logs, rocks or vegetation. The eggs are guarded by the male and take 14-21 weeks for the eggs to develop. There is no free-swimming tadpole stage and the young climb onto the dorsal surface of the male and continue their development there. During this time they remain fairly inactive.

These frogs prefer cool misty evenings and are particularly active above ground when the temperature is between 8 and 14 degrees Celsius. They show considerable site fidelity and tend to stay with a 5m radius for years at a time. They are very long lived with some individuals being found thirty years after they were marked.

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                           Archey's Frog (Leiopelma Archeyi)

Archey’s Frog Leiopelma Archeyi is the smallest of the indigenous species (<38 mm). They are restricted to two regions on the North Island of New Zealand, occurring on the Coromandel Peninsula and the Whareorino Forest, west of Te Kuiti. They prefer to live at a relatively high altitude from about 400-1000 m in moist native forest; they are terrestrial and nocturnal, spending most of the day hidden under stones or logs away from streams or creeks. Leiopelma Archeyi is a terrestrial breeder, laying a small clutch of eggs in a moist site under stones or logs. They exhibit parental care with the tailed froglets remaining on their father’s back for several weeks until metamorphosis is nearly complete. Populations of this species have crashed in recent years with monitored populations decreasing by 88% over the 1996-2001 period. Several factors, including the severity and rapidity of the population crash and the geographic spread of the decline, , all point to disease being the major cause of the reduction. A breeding facility has recently been opened at Auckland Zoo with the intention of producing a self-sustaining captive population. A top priority of the New Zealand Native Frog Recovery Group is to investigate ways of preventing further declines of this species. This frog is listed as Critically Endangered.

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              Hochstetters Frog (Leiopelma Hochstetteri)

Hochstetter’s Frog Leiopelma Hochstetteri is the more aquatic frog of the four living species. It is widely distributed in at least 10 fragmented and isolated populations in the northern half of the North Island. They are nocturnal and shelter by day in wet crevices or under stones or logs close to the water’s edge in shaded streams. Males of this species exhibit sexual dimorphism in the form of more muscular, robust forelimbs than females. This is another distinctive trait, as the other three Leiopelma species are not sexually dimorphic, apart from females reaching greater body size. One of the main threats to this species is the destruction and modification of its habitat, which is still occurring either directly (e.g. forestation, gold mining, storm water discharge) or indirectly (e.g. feral goats and pigs causing erosion leading to stream dilatation). The New Zealand Department of Conservation has purchased considerable amounts of suitable land to prevent further degradation of some of their habitat, and attempts are being made to better monitor their populations. This frog is listed as Vulnerable.

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                      Green and Golden Bell Frog (Litoria Aurea)

The Green and Golden Bell Frog, Litoria Aurea, is a magnificent looking frog and can often be mistaken for a garden ornament!  In the late 1860s several consignments of these frogs were received from Sydney and released.  There have been several attempts to establish populations of this species in the South Island, but it appears that the climatic conditions are not favourable and the species is restricted to the upper half of the North Island (north of Gisborne).  They occur around the same ponds as the Southern Bell Frog and may interbreed. These frogs are brilliantly coloured with an overall green appearance interspersed with gold or bronze coloured patches.  There is a fold of skin (usually cream in colour) running from the eye along the side of the animal to its groin.  This fold is bordered by a thin black line that continues over the head to the nostrils.  The back of their thighs and groin area are bright blue and the belly is smooth and white.  The skin is very smooth and there is only webbing on their hind feet.  They have suckers for climbing on all toes and fingers.  Males are smaller than the females with an average length of about 60 mm, whereas females can be larger than 90 mm. Their deep nasal call has been described as a drawn out guttural four-part, and large choruses can sound like motorbikes from a distance. These frogs are commonly found perched on aquatic vegetation or fallen trees near breeding sites. The frogs prefer temporary ponds in full sunlight that are usually shallow and free of aquatic predators such as Mosquito fish.  They are quite unusual in the frog world in that they like to bask in the sun and are active during the day.  They breed during the summertime with the males calling from the water’s surface.  Females may lay between three and ten thousand eggs in a floating gelatinous mat, which sinks after 6-12 hours. The eggs hatch into tadpoles after about two days, and metamorphosis occurs about two months later.

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                    The Southern Bell frog (Litoria Raniformis)

The Southern Bell Frog, Litoria Raniformis, is similar in colour and size to the Green and Golden Bell Frog, but has a lot more warts and less golden coloration. This species was introduced to New Zealand in the late 1860s from Tasmania by the Canterbury Acclimisation Society. They have been very successful in New Zealand and can now be found throughout most of the country. These frogs are the largest frogs to be found in New Zealand with females reaching over 100mm.  They are similarly coloured to the Green and Golden Bell Frog but often have a warty back. They generally have more dark brown or black blotches on the back and there is always a pale green stripe down the middle of their back (although this can change in intensity depending upon environmental conditions). The back of their thighs and groin area are bright blue to turquoise and the belly looks granular. The fingers lack webbing while the toes are almost completely webbed.  There are no suckers on the ends of their toes or fingers. The call is similar to the Green and Golden Bell frog but is not as drawn out (in Australia it is also known as the Growling Grass Frog).  Males usually call while floating in water. The breeding details are very similar to the Green and Golden Bell frog except that this species seem to prefer permanent lakes, swamps and dams with still water.

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                    Brown Tree frog (Litoria Ewingii)

The Brown Tree Frog, Litoria Ewingii (sometimes referred to as the whistling frog) was thought to have been introduced to New Zealand on only one occasion.  Frogs and tadpoles of this species were caught in Tasmania and released in Greymouth  (South Island) by W. Perkins in 1875.  Although only one other documented translocation is reported for this species, from Greymouth to Manawatu, it has now become quite widespread over all of the South Island and most of the southern and central North Island, with the odd record in the northern areas. The wide distribution of this species is probably a result of human-mediated liberations rather then a natural spread of the frogs through self-seeding activities. The brown tree frogs are generally an overall light brown colour, although this may vary from a white/grey to a dark brown background. They all have a white stripe along the jawline from the armpit, to below the eye and sometimes to the end of the snout. Most frogs have a lighter patch on the top of the head, extending from between the eyes to the tip of the snout. The belly and throat are usually white or cream and the undersides of the thighs are bright orange. The eardrum is quite distinct and easily visible and this characteristic alone separates this species from our native Leiopelma species. The fingers and toes have slightly expanded tips that are used for climbing, and webbing is usually absent. These are generally quite small frogs ranging from about 30-50 mm long. The call is characteristic of this species and is distinctly cricket-like.  The call can be described as a high-pitched trill repeated 5 or 6 times. Although in several books this species is referred to as the Whistling tree frog, the common name Brown Tree frog is preferable as the call doesn’t sound anything like a whistle! These frogs are quite unusual as they can breed throughout the year in favourable conditions. During rainy spells males can be heard calling] and tadpoles can be found in most months of the year, even when there is frost around. The males usually call from concealed positions within vegetation around ponds and streams.  These frogs have external fertilisation and clumps of eggs are laid underwater sticking to submerged plants. The tadpoles are black when they first hatch and gradually turn brown as they get older. They are quite difficult to tell apart from those of other introduced species.

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            Unsuccessful introductions

These species were introduced to New Zealand but did not establish populations here.  It is presumed that these animals died out, as they are no longer present.

Common frog (Rana Temporaria) introduced from England to Canterbury in the 1860s, but failed to establish.
 
Edible frog (Rana Esculenta), similar in appearance to the Common frog, introduced from Europe to the Nelson area in 1860s and also failed to establish.
 

The Common toad (Bufo Bufo) was a likely choice as it enjoys the British climate.  It was introduced in the late 1860s and again in the 1890s, however they failed to establish both times.
 

White's Tree Frog (Litoria Caerulea) was introduced from Australia to New Zealand in 1897 and 1899 and liberated at several sites around the country, followed by an accidental import in the 1940s.  However, there have been no sightings since the 1950s, and it is assumed that the species did not establish.
 
One individual of the Dainty Green Tree frog (Litoria Gracilenta)  arrived in New Zealand on rigging of a ship from Australia in 1972 and has not been seen since.
 
Several Slender Tree frogs (Litoria Adelaidensis) were reported in New Plymouth in 1981, however no evidence of an established population has been found.

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                                                         Conservation Status

Sub-fossil records indicate there were at least seven species of native frogs in New Zealand before the arrival of people approximately 1000 years ago. Habitat change and the introduction of non-native mammals have caused the three largest frog species to become extinct. The remaining four New Zealand frog species all have severely reduced distributions and populations sizes.

 Archey’s frog - Critically Endangered
Sub-fossil records and the two remaining disjoint populations (Coromandel Peninsula and Whareorino) suggest the mainland range of this species was once more widespread. A sharp population decline was detected in the late 1990’s and this species is now in critical danger of extinction. 

Hamilton’s frog - Critically Endangered
One of the world’s rarest frogs with an estimated population of less than 350 individuals. These frogs survived only in a small rocky area on mammal-free Stephens Island in the Cook Strait. Sub-fossil indicate Hamilton’s frog was once widely distributed throughout the lower North Island and upper South Island. 

Maud Island frog - Endangered
Also restricted to a single island in the Marlborough Sounds following the arrival of humans in New Zealand. An estimated 40 000 frogs survive in a remnant of regenerating forest on rodent-free Maud Island.

 Hochstetter’s frog - Vulnerable
Ten populations of this species are known in the upper half of the North Island. The fragmented distribution of these populations suggests the distribution of this species has become reduced following the arrival of humans. 

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                                SAVE THE FROGS!
One of the best ways of helping out with the research and conservation effort is by making a donation. No matter how large or small the donation, all proceeds take us a step closer toward our goal of maintaining the unique amphibians of New Zealand, and increasing our knowledge of these special animals through research.  
                        Why donate?

As well as manpower, all current and future research and conservation efforts require money. Native frogs receive much less attention than charismatic, larger animals, such as kiwi and kakapo that inhabit this country, however they deserve the same amount of attention and respect as unique and archaic animals!
             
             What your donations could achieve

All proceeds will go towards current and future research projects and the fund is audited by the University of Otago.  Some important areas of research that are partly funded by contributions include:

• Captive breeding programmes
• Chytrid fungus research
• Translocations of native frogs
• Monitoring methodology and population studies
   

For a complete list of NZ frog projects that your funds would support click here.

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