Hedgehogs…know your pest!

European hedgehog (Erinaceus europaeus occidentalis)

Identification and habitat
Introduced to take care of snails, slugs and other garden pests, NZ lacks most of the means that would have controlled their population in their native home in the U.K. As a result, they are now much more numerous here than their home country.

They are instantly recognizable. They are grey-brown in colour with their back and sides entirely covered with spines.
They are 150-250 mm in overall body length and reach a maximum of around 1 kg, but their weight can drop dramatically during winter hibernation.

Habitats
Hedgehogs are widespread across the whole country. In many areas of New Zealand, there are now estimated to be between 2 and 4 hedgehogs per hectare (and in some areas as many as 8).
Hedgehogs’ preferred habitat is lowland pastoral areas, and they become less common with increasing altitude.

Behaviours

• They are nocturnal mammals, meaning they will do almost all their hunting at night.
• They have a very keen sense of smell, which gives them a great advantage over our native species.
• They eat mostly insects but will eat small skinks, frogs and birds’ eggs and chicks. They have often been referred to as “ground hoovers” for their ability to hunt and eat anything on the ground.
• They are excellent swimmers and can climb for food.

Threats – why are they a problem?

• They are a spill-over host of bovine tuberculosis (Tb), meaning they are likely to host it if possums in the area also carry Tb.
• Ground nesting birds are particularly vulnerable to hedgehog predation. This includes many native and threatened species such as the banded dotterel and the pipit.
• Threatened larger invertebrates such as wētā are heavily impacted by hedgehogs, and one hedgehog elsewhere in NZ was found with 283 wētā legs in its stomach.
• Hedgehogs are voracious eaters and can have devastating impacts on local skink populations, especially in cooler weather when lizard activity declines.