Mulbarton Common – Building a Hibernaculum

Friday 18th March 2016

If you were to ask the average person in the street – ‘What is a hibernaculum?’ – I suspect that they would scratch their head a bit before admitting that they didn’t know. If that person was a zoologist, they would almost certainly know. Many people, in the last two to three years, will have acquired one and will call it either a ‘bug’ or ‘bee’ house.

Bee House
Bee House

A hibernaculum (Latin for “tent for winter quarters”) is a place of abode in which a creature seeks refuge, such as a bear using a cave to overwinter, or insects and reptiles may hibernate in to survive the winter.

Today we were on ‘Mulbarton Common’ building a hibernaculum, but one quite a lot bigger than a bee house. The Common is a large area of grassland (about 45 acres) which contains several ponds and will support an extensive range of animal life. In an effort to try and help sustain these populations, we are constructing an amphibian hibernacula close to one of the ponds which should have many amphibians in it over the summer months that would have spent the winter away from the water. As well as the amphibians there will be small mammals, snakes and insects which would make this their winter home.  Some may even build a nest in it.

Blog 28
Constructing the hibernaculum next to pond on Mulbarton Common.

The structure we built is about 3m x 2m and stands over a meter in height. We started out by removing the turf and laying it to one side, then we removed some more earth to a depth of approx. 5 – 6cm. Into this shallow scrap we loosely placed some logs (of various lengths and thicknesses) in a very haphazard way and mixed in bundles of brash, reeds and some leaves. Constructing the hibernacula in this way creates a labyrinth of passages, nooks and crannies for our intended inhabitants to be isolated from each other.  This wood pile was then covered with the soil and turf which we had previously put to one side. We had to make sure that around the base there was plenty of gaps between the logs for the intended inhabitants to ‘come and go’. The finished item looked more like an ancient barrow, of which I am sure, any ancient war lord, would have been very proud of. Well if he wasn’t, he should have been, because, we were all proud of our days’ work.

Written by Alan Rae, Norwich Fringe Project Volunteer