Posted by Cathy Nottingham @cathy28495357 

Hedgehogs are an underrated mammalian pest in New Zealand – there are even groups of people who ‘rescue’ them.  Hedgehogs have been shown to have an impact on native ground-nesting bird, lizard and weta populations, but little research has been carried out on them in urban environments. In particular, we don’t know what their impact might be in urban forest patches (fragments).  That’s where I come in, for my Masters research project, I’ll be investigating the impact of hedgehogs in urban forest fragments.  I’ll look at what hedgehogs are feeding on in this environment through gut content analysis.  I’ll also be working on understanding the relationship between the number of hedgehogs in a forest fragment and the severity of the impact. This is called a damage function. This will enable managers and community groups to initiate hedgehog control once their abundance surpasses a critical impact threshold.

Hedgehog. Photo credit: Gaudete / Wikimedia Commons / CC-BY-SA-2.5

Having recently received permission from the council to start working in the reserves, I’ll will be soon heading out at night to find hedgehogs.  This will involve using thermal imaging cameras, volunteers and some oven mitts!

Thermal image of a bird using Seek Thermal Camera

As part of creating a damage function, I’ll be using crickets (as a proxy for weta) and quail eggs to measure survival or death by hedgehog. Camera traps will be used to monitor predation by hedgehogs, and the survival rates of the experimental crickets and eggs. I’ll be using chew cards to monitor the relative abundance of hedgehogs and rats in the reserves. With councils and community groups increasingly controlling rodents in bush reserves to help native birds, might this let the hedgehogs run rampant?  So remember, next time you see one of these prickly pests, ambling along at night, there is a killer in your midst, but I’m on the case, and I’m planning on finding exactly what they are up to in our urban bush patches.

Trialling predation experiments: using crickets and camera traps to monitor hedgehog predation

Cathy is a MSc student in the Centre for Biodiversity & Biosecurity, School of Biological Sciences, University of Auckland. She is investigating the impact of hedgehogs in urban forest fragments. She is supervised by Margaret Stanley and Al Glen.