The threat of hedgehogs
Ecological Impacts
Hedgehog juvenile
The extent to which hedgehogs impact upon the New Zealand environment is only recently beginning to be understood in any detail. Here is a summary of findings so far:
- Hedgehogs are proven to be a major predator on eggs of riverbed breeding birds such as banded dotterel and black-fronted tern, and have been known to kill and eat chicks of a variety of ground-nesting birds.
- In the MacKenzie Basin (South Island), hedgehogs have been found to be responsible for one in five predator attacks on nests.
- Hedgehogs have a voracious appetite for invertebrates and take many local endemic species. They are known to eat the rare giant native centipede and a number of other rare insects.
- One hedgehog was found with 283 weta legs in its stomach!
- They have been known to eat the native snail Wainuia urnula. Lowland populations of Powelliphanta snails may also be severely affected, particularly the Patarau and Otaki sub-species. Only smaller (juvenile) snails are eaten, but this severely affects recruitment and population recovery.
- Hedgehogs also prey upon lizards, particularly in cooler periods when lizard activity slows. Skinks are particularly at risk.
- It is possible that hedgehogs also prey on endemic frog species, as they are known to take introduced frogs and their range overlaps with some NZ frog species.