The following is a comprehensive, well-researched study of predatory animals and their behavior in New Zealand. This research indicates that cats are the least of Raglan's problems as related to bird predation. Read and learn!
Cats: top predator?
The idea that Cats must Go, put
forward by Gareth Morgan fails to take account of the multiple predators
introduced to New Zealand over time. A fairly cursory look at Te Ara produced
the following information, which puts the predation by cats in perspective. You
may be surprised to find that the cat is an ‘also ran’ usually beaten out of
first place by rats and mustelids (stoats and weasels). Don’t believe me? Check
out the original entries in the Encyclopedia. You will find that I have
faithfully copied the information across.
Excerpts from Te Ara, The
Encyclopedia of New Zealand.
{Kiwi} Predators
Because kiwi hatchlings are left
at such a young age, they are vulnerable to predators. It is speculated they
might have become nocturnal to avoid the Haast’s eagle, now extinct.
Introduced animals are a more
severe threat. The most dangerous are stoats, which feast on the young birds.
Kiwi chicks can resist stoat attacks once they weigh about 1 kilogram, but this
is not until they are 40 weeks old. Other predators include dogs, feral cats
and even wild pigs, which dig up kiwi burrows. Weka are known to eat kiwi eggs.
Only about 5% of wild kiwi chicks
survive the first six months. Once there were an estimated 12 million kiwi, but
by 2006 there were fewer than 100,000.
{Rabbits} Trying to
control Rabbits, Methods that have been
tried include: …
·
using predators such as ferrets,
stoats and weasels. These were released in New Zealand, but they hunted native
birds, and did not kill as many rabbits as expected
….
Robert Peden.
'Rabbits', Te Ara - the Encyclopedia of New Zealand, updated 9-Nov-12
URL: http://www.TeAra.govt.nz/en/rabbits
{Lizards}
Predators
Mammal predators pose the biggest
threat to native reptiles. Kiore or Pacific rats (Rattus exulans)
arrived with Polynesians about 1250–1300 AD and caused the extinction of some
lizards on the mainland and on the smaller islands. In the late 1700s and early
1800s, European rats, mustelids (ferrets, stoats and weasels) and cats caused
another wave of local extinctions.
Extinctions
At
least three lizard species have become extinct since people first discovered
New Zealand. Eight species have become extinct on the mainland but survive on
islands where there are few predators. Those surviving on the mainland are less
common than they once were.
Large,
nocturnal species are most likely to become extinct, as mammalian predators
usually hunt at night. For example, all large species in the genus Oligosoma are
nocturnal. Large species are all but restricted to rat-free islands, and small
species still occur on the North Island. All were once widespread across the
North Island. Even large, day-active lizards are vulnerable to predators and
today occur only in small, widely separated populations – just a portion of
their original range.
Endangered
species
Almost
half of New Zealand's reptiles are threatened or endangered. It is now illegal
to handle or keep in captivity any native lizard without a permit from the
Department of Conservation.
Some, such as the spotted skink (Oligosoma lineoocellatum), are still widespread,
although their numbers are probably dwindling. Others are endangered, including
the Otago and grand skinks, two of the country’s largest (up to 30 centimetres
long). They live in mountain tussocklands in Central Otago, but occupy only
one-tenth of their original range. The reason for this is unclear. They may
have fallen prey to cats, especially in winter, when cats are hungry and
lizards slow. Natural fires and agricultural development are also threats.
Research is under way to manage these hazards and help these species recover.
Until
recently there have been few attempts to save endangered or rare reptiles from
extinction. The eradication of rats from islands such as the Mercury Islands
off Coromandel Peninsula has brought new hope for some lizard species. Rats are well controlled by cat populations.
Kerry-Jayne Wilson.
'Lizards', Te Ara - the Encyclopedia of New Zealand, updated 9-Jul-13
URL:
http://www.TeAra.govt.nz/en/lizards/sources
{Weta}
Giant wētā
Giant
wētā (genus Deinacrida) are
predominantly herbivorous. They are not as social as tree wētā and tend to
occupy temporary, poorly protected shelters by day, which exposes them to
predators.
Giant
wētā did not survive long in lowland areas after the arrival of humans and rats
in New Zealand. Of the 11 giant wētā species, only six still occur on mainland
New Zealand – in the South Island mountains, above the level where rats live.
The other species now survive only on offshore islands.
Wētāpunga
The most impressive wētā is the
wētāpunga (Deinacrida heteracantha), a species of giant wētā now confined to
Little Barrier Island. Females reach a body length of 7.5 centimetres, and
their hind legs are 13 centimetres if stretched out. Like other lowland giant
wētā species, these giants of the insect world were extinct on mainland New
Zealand by 1900, killed by rats.
