Pest animals and plants

Rats

Species – Three species of rats have been introduced to New Zealand: ship rat (Rattus rattus), Norway rat (Rattus norvegicus) and kiore/Pacific rat (Rattus exulans). The two species found in the Eastern Bays are the ship and Norway rats.

Habitat – Rats are found in most habitat types and are widespread in mainland New Zealand. Norway rats, in particular, are associated with urban areas.

Threat – Rats are omnivores that kill and eat many native birds, reptiles, invertebrates and plants. Rats are good climbers so can predate birds, eggs and chicks in treetops.

Home range – Norway rat: 0.8 – 21ha, Ship rat: 0.3 – 11.4ha.

Possums

Species – the Brushtail possum (Trichosurus vulpecula) is the only species found in New Zealand.

Habitat – possums are found in most habitat types and are widespread in mainland New Zealand. Their preferred habitat is forest, therefore, they are likely found in higher numbers in forest fragments in the project zone such as Dingle Dell, Churchill Park and Kohimarama Valley Forest.

Threat – possums are a major predator of native plants as they eat buds, flowers, fruit, seeds and shoots. Additionally, possums have been observed eating native bird eggs and chicks, as well as invertebrates.

Home range – Male: 0.7 – 3.4ha, Female: 0.6 – 2.7ha

Mustelids

There are three species of mustelids in New Zealand: stoats (Mustela erminea), ferrets (Mustela furo) and weasels (Mustela nivalis).

Species – The mustelid most likely to occur in the Eastern Bays are stoats, although llikely only in small numbers.

Habitat – Mustelids occur in a range of different habitat types, with ferrets preferring open country. Mustelids will often follow stream edges, bushland edges, ridges, fencelines, fallen trees, tracks and roads.

Threat – Stoats are ferocious predators and are the number one killer of New Zealand’s endangered species. Stoats and weasels are good swimmers and can prey on animals up to three times their body weight.

Home range – stoats have a home range of 200 ha 

Hedgehogs

Species – there is only one species of hedgehog in New Zealand, the European hedgehog (Erinaceus europaeus occidentalis).

Habitat – hedgehogs can be found in all habitats, including urban, rural, braided river and forest areas

Threat – hedgeshogs eat a range of native invertebrates and reptiles as well as the eggs and chicks of ground nesting birds.

Home range – 1.4 km2