A wild few weeks: the big hedgehog hunt

Cross posting from the Suffolk Wildlife Trust blog.

It’s been a pretty wild few weeks: out till 4am, police call outs and raunchy behaviour witnessed on the streets of Ipswich.

I am of course talking about our night hedgehog surveys, walking set transects until around 4am, donned in high vis and torches for fieldwork we are conducting for Nottingham Trent University. The research, being led by Dr Richard Yarnell and PhD student Jessica Schaus, is validating a method of estimating hedgehog population density.

Whilst we know that hedgehog populations are declining, estimating population sizes/densities is tricky. Current methods tend be intensive, invasive and not applicable across different habitat types. The method being validated by us and other researchers across the country is the Random Encounter Model.

The Random Encounter Model uses randomly distributed trail cameras across a study area and utilises information on detection rates, the size of survey area and distances hedgehogs are moving to estimate densities, without the need for identifying individuals. The benefit to this method is that it is completely non-invasive and can combine awareness raising with research when recruiting garden owners to install cameras. 

To determine whether the REM method would be a valid way of estimating densities, it was our job to collect data for both the REM method and the standard mark-recapture method currently commonly used. So, as April approached, I was busy setting up our second field site in Ipswich and recruiting volunteers to join me in becoming nocturnal for the Spring.

Our night work got off to a slow start with only one hedgehog found in several nights, and who can blame them, it has been a very strange (and late) Spring this year (with thanks to Beast from the East). We did however find LOTS of toads in amplexus (ie. the raunchy behaviour), many smooth newts and the odd mouse, and we can’t really blame residents for calling the police on us – we did look a little odd patrolling the streets and searching bushes at 3am in the morning (I hasten to add the police were very friendly and happy to chat to us about hedgehogs before we went on our way!)

After a slow start we did, thankfully, start to catch more hedgehogs. After undergoing a health check, individuals were given a unique mark and if certain criteria met, a satellite tracker attached so we could see exactly where these hogs were travelling (all of these activities were done under license).

My favourite part of the transect was the allotment, because although it did feel really quite creepy (with some horror film worthy scarecrows), there was lots of great habitat to explore, and it was really exciting when we finally found a hedgehog on one of the plots. When tiredness sets in, EVERYTHING starts to look like a hedgehog. A couple of cabbages and an old swede were incredibly deceptive in these early hours, and we very nearly missed the hedgehog, at first assuming it couldn’t possibly be anything other than a vegetable.

Whilst a pair of drunken chaps on the bank holiday weekend wanting to join in on the ‘hunt for harry the hedgehog’ were probably trying to help, the people I really want to thank are all of our amazing volunteers that walked many many miles during the early hours of the night, and who without, the survey wouldn’t have been possible! [I’ve just worked out that I walked over 200km during this night period, so there really was a lot of walking!)