Pest animals and plants

Pest animals

The Eastern Bays Songbird Project primarily targets rats (Rattus spp.) and possums as these are considered the main pests in urban areas such as the Eastern Bays. However, predatory hedgehogs are also found in the area and mustelids (stoats, ferrets, weasels) may also occur in small numbers.

See the get involved tab for methods to control pest animals.

Ship rat. Image by Ngā Manu Images, retrieved from:


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.

Brushtail possum. Image by Ngā Manu Images, retrieved from:


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

Stoat. Image by Ngā Manu Images, retrieved from:


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 

A hedgehog on the forest floor. Image by Ngā Manu Images, retrieved from: 


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

Pest plants

Auckland is the weediest city in New Zealand and a multitude of pest trees, vines and groundcovers can be found within the Eastern Bays. See below for some information on the common weed species in the Eastern Bays and which native species you could plant instead. 

Weed Control Advice flyer.pdf
Dealing with Moth Plant john la Roche.pdf