Hedgehogs were first introduced in New Zealand in the 1870s to make British settlers feel more at home. Now, 150 years later, the impact hedgehogs have on our native species is only just being understood.
For a long time they were seen as innocuous garden inhabitants, but with more research the picture is becoming clear. Hedgehogs pose a real threat to our already vulnerable invertebrates, lizards and ground-dwelling birds.
With our childhood memories of feeding them milk on saucers, many New Zealanders struggle to reconcile the fact that hedgehogs impact our native species, so we’ve pulled together seven facts so you can learn more about them.
1. The hedgehog population in New Zealand is more numerous than in their native homeland, the United Kingdom
New Zealand has one of the world’s largest introduced hedgehog populations. In many parts of the country there are an estimated two to four hedgehogs per hectare (a hectare is approximately the size of a rugby field) and in some areas there may be as many as eight!
2. Hedgehogs are excellent swimmers and climbers
Did you know that in a single night, a hedgehog can swim over 800m in search of food? Hedgehogs are also adept climbers that can climb hedges and high walls.
3. A hedgehog shocked researchers recently by appearing nearly 2000 metres up a mountain in the Mackenzie Basin
Hedgehogs are abundant through the lowland and coastal districts, less numerous in hills and are scarce in mountainous areas, although their presence in these areas may be increasing.
They are scarce or absent in areas where rainfall exceeds 250 cm/year or where more than 250 frosts occur annually.
4. One hedgehog was found with 283 wētā legs in its stomach
Wētā have six legs which means approximately 47 wētā were eaten in a single night’s foraging. This hedgehog was found while research was being done in the upper Waitaki basin area. They were looking into the diets of hedgehogs and the implications for conservation.
In the same study, 22% of hedgehogs were found to have wētā remains in their stomachs.
5. Hedgehogs often eat 160g of invertebrates per day
To put that into context, that could be up to 53 Auckland tree wētā given they weigh between 3 – 7g.
6. Hedgehogs eat more than slugs and snails
They eat a varied diet that can include frogs, mice, lizards, skinks, eggs and chicks.
In a 2005 New Zealand study, three times as many adult female hedgehogs had lizard remnants in their stomachs compared with adult males. This may be linked to the high energy demands of females during breeding season.
7. Hedgehogs prey on chicks up to the size of two week old chickens
For ground-nesting birds like banded dotterel, hedgehogs are a major threat. They eat their eggs and kill the chicks.
In the MacKenzie Basin, hedgehogs are responsible for one in five predator attacks on nests.
Did you already know these hedgehog facts? Did any surprise you?
- Diet of hedgehogs (Erinaceus europaeus) in the upper Waitaki Basin, New Zealand: Implications for conservation.
- Pest Detective – Hedgehogs.
- One News – Prickly pest shocks conservationists as hedgehogs spotted 2000m up NZ mountains.
- Department of Conservation – Hedgehogs.
- Home and Roost UK – Can Hedgehogs Swim?
- R.E Brockie – Distribution and abundance of the hedgehog (Erinaceus europaeus) L. in New Zealand.
- Blue Mountains study shows 1080 effective – even for hedgehogs, mice.