Hedgehog in the grass

Photo: Hedgehogs are found right across the motu. Photo credit: Simon Gooding.

Our Pest Free Banks Peninsula programme is removing a number of pest species off Kaitōrete, including mustelids (weasels, stoats and ferrets), possums, feral cats and the hedgehog, all to help save and restore our precious ecosystems and taonga species.

It’s a funny thing. Hedgehogs have had this incredibly effective cute-washing campaign for years. Think Beatrix Potter and other children’s story’s featuring garden animals. However beloved, we need to recognise that they have real impacts on New Zealand’s special creatures, because they are above all else, very effective ground hoovers.

There is plenty of trail camera evidence of hedgehogs getting tucked into birds’ eggs, chicks and lizards; and scat has shown up all the indigestible parts of various beetles that they consume. We know that they are predators in Aotearoa, but some prey species eaten by hedgehogs can go unnoticed as they are soft-bodied (as in easily digestible and not seen in scat) and not likely to be seen on camera. So how do we know exactly what else hedgehogs are impacting on?

Kupe's grassmoth sitting in foliageBanded dotterel female looking at the camera

Photos: Kupe's grassmoth (L) and pohowera/banded dotterel (R), two species that would benefit from hedgehog removal. Credit DOC.

While there is plenty of research on hedgehogs overseas, there is much less on how hedgehogs use our landscape here in NZ. And Maryanne Walker, Lincoln University MSc student, along with her mentor Dr Alison Evans from the Christchurch City Council, are about to delve deeper into hedgehog diet preferences – especially on our ecologically important site, Kaitōrete.

They intend on using a study method first proposed by Arsalan Emami-Kyoyi on their study on NZ fur seals. This means that they are looking to collect scat samples in the field and will be using eDNA techniques to identify species against an international DNA (Barcode) database. This will mean that some samples from our native species not yet sequenced will also need to be collected and sent away to be compared against scat samples. This technique should show what the hedgehog has eaten that would otherwise be undetectable under a microscope or seen on camera. While this explanation is simplistic, it gives you an overall understanding of what they are trying to achieve.

Essentially, it is a non-invasive way to detect the diet of hedgehogs, to know what damage they may be causing and to emphasise the need for controlling them. Exciting stuff!

Let’s learn a little bit about Maryanne to start with and we’ll let her tell you about where her study will be going.

Karin and Maryann with Nightshade/Mabob the hedgehog dog

Photo: Karin (PFBP conservation dog handler), Nightshade and Maryanne at the idyllic Kaitōrete site.

Hi Maryanne, so pleased to see you tackling an important area of study! How about you tell us a little bit about yourself?

I'm originally from Nelson and that is where most of my family is still. I was lucky that my dad has a bach at the Nelson Lakes, Rotoiti, so I essentially grew up with every holiday in the bush or on the lake. I also have an aunt who’s an entomologist so always saw cool invertebrates and learned about them. 

But surprisingly I actually came to Lincoln University to study a Bachelor of Agricultural Science, influenced by my mum's father who is a small-scale sheep/beef farmer. I have always loved science and being around animals so farming made sense back then. I stuck with it for a year and a half till I took an extra class – an entomology course, and I fell in love with the creepy crawlies! Looking back, I feel crazy doing 5 classes through covid but feel so fortunate to have done that as it influenced me to change my whole degree.


To be fair, invertebrates are pretty cool. What else drew you into conservation?

I completed my Bachelor of Science - in Conservation and Ecology in 2021 and completed two summer scholarships with the Pest Management and Conservation department. This included an invertebrate survey on Banks Peninsula across the Wildside, and the second was a lizard survey in the same areas. I thoroughly enjoyed these, both from being out in these amazing locations, as well as connecting with a bunch of cool landowners and Banks Peninsula Conservation Trust people and hearing their stories. But mostly because of exploring the habitats and seeing what influenced abundance hands-on instead of just reading about it. 

I’ve also done lab demonstrating and field assistant work. It honestly feels like I'm just going on an adventure and having fun and I get to call it work. 

I feel pretty lucky to have found conservation and now I’m in, I think I'm hooked. I am currently working towards an MSc majoring in conservation and ecology.


So how do you go from invertebrates to hedgehogs?

While considering a research topic for my master’s, Dr Cor Vink (my Lincoln University supervisor) suggested a project that he and Dr Evans had wanted a student to get their hands on. Initially, I was hesitant and the DNA/molecular side of it was a bit daunting, but in the end, I decided that this was an opportunity to up-skill in an area that isn’t common, yet will have a growing demand in, while still staying relevant to entomology.


What do you hope comes out of your research?

With my research, I hope that it can be used to open people's eyes to the damage that the 'not so cute' hedgehogs are doing. It seems to be a common theme that people always mention hedgehogs being an unmeasured threat, well now I'm hoping we can get some quantified impact to add to their conviction.  

Additionally, if the methods used are successful for hedgehogs, then they have the potential to be adapted for other mammalian species to explore the complete diets of these species. 

Katipo spider clutching two egg sacs

Photo: Kaptiō spider clutching egg sacs. Found on Kaitōrete in the sand dunes.


It’s such an exciting area to be in, well done so far! What would you say to other students thinking of getting into conservation research?

My advice would be to ask lots of questions, make as many contacts as you can and say yes to opportunities when they come. My career has never felt structured like I knew where I was going, and I still don't. I've been spending it following the serotonin and exploring what I found interesting. Don't worry about your friends thinking you are weird for crawling on the ground turning over logs looking for beetles (metaphorically or literally), before you know it, you'll find it hard to turn over a log without a like-minded friend by your side.


From us at Pest Free Banks Peninsula, we look forward to seeing how you get on in your study! Any information we can get to understand species like hedgehog, brings us all one step closer to understanding how to eliminate them and help our native species thrive once again.