The usual ways to survey for Common Dormouse are by putting up nestboxes to see if they get used; or searches for hibernation nests in winter; and most popular – searches for hazel nut shells, which are nibbled in a very particular way by dormice!
(See a photo… ) (Heiselmaus; Nëss a Friesspueren)
We tried these methods at Sheepdrove Organic Farm in 2002 and 2003 without success. However, after finding a rather distinctive nest on the farm (in a bumblebee box!) I’m hopeful that we might have dormice at Sheepdrove. Certainly it is possible, and if we confirmed this mouse was here, it would be fantastic. Another rare mammal we that know we have is the meek and mysterious Harvest Mouse.
Sheepdrove’s farm wildife volunteers will be surveying for signs of these mice this year. Join us if you like…
Meanwhile the volunteers and I have built some dormouse nestboxes, using a simple, multi-use nestbox design that I came up with. I adapt this box for small birds and bats too.
Click pictures to enlarge.
You can make this easily out of untreated timber – choose larch, cedar or oak if you want your box to last more than a few years. Rough-sawn timber is fine, but watch out for splinters.
My simple dormouse nestbox design doesn’t involve difficult joinery – it suits the novice box builder. Start with a board just 1 metre long, measuring approximately 150mm X 25mm (6″ x 1″). Saw off 3 lengths of 200mm each. Saw one of those up diagonally – cut from corner to corner – to provide the side panels. One of the whole 200mm sections is your floor, the other is the front. The 400mm section remaining is the roof. Simple!
The pictures above show you how the 5 pieces fit together.
The box offers plenty of room for a woven nest. The large roof keeps off the rain. If you’re concerned about the floor gathering rain from the tree-trunk, cut away the central two-thirds or so. Make the box inspectable by having a hinge on one side, and use a screw for secure closure.
Face the dormouse box towards the tree where you mount it. That prevents most birds from finding the hole (not Blue Tit) and keeps the cavity cosy. Fix the box in place by using wire, wrapped around one or two screws on each side of the box, and then around a branch. Prevent the wire digging into the tree by wrapping a short piece of cloth around the top wire. Adjust it each year, to allow for growth.
Because you haven’t nailed it to the tree, the box can be inspected and monitored. You need a licence to disturb Hazel Dormouse in this way. Dormice are fascinating and it’s well worth attending a Mammal Society training workshop. (Read a great book on dormice… )
To use this as a bat box, you don’t have to do anything, but I would recommend that you change the entrance for bats, if that’s what you want in here. For bats, ensure the entrance hole is much shallower – maybe 15mm deep by 50mm wide; sawing a very small gap at the base of the door panel does the trick. Actually this design started upside-down as a bat box! This can also be turned upside-down to become a nestbox for tits.
Please try out my design and improvise to suit your favourite wildlife…