Here's how you can help with hedgehog hibernation

Build it and they might come — if the bats, frogs, and other creatures wake from their slumbers. Fiann Ó Nualláin offers some tips.

Last week we took a look at some hotels and habitats to help overwintering butterflies, bees, and garden-friendly insects. This week, for the weekend that’s in it, I thought we should look at conducive environments for those other creatures preparing to hibernate right now — bats, warty toads, and spiny creatures.

Hibernation we might think of as a winter sleep but in fact, it is a stasis scenario were animals stock up on fat reserves and slow their heart rate and breathing down to minimum. Some even lower their body temperature and limit movement in order to survive off the fat reserves over winter.

This is why it’s important to not just create a mock-up shelter but make sure that it is stable and secure and that the animal inside won’t have to evacuate early or be buffeted by winds or nosey pets. So placement is key and sturdiness of structure is vital. Don’t skimp on materials — an upcycled pallet or wine crate is better than a cardboard packing box.


Bats tend to hibernate from November until April. They often opt for hollow trees, roof spaces, and, not just in horror movies, dark caves. So while most bats will slow their heart rate to as little as 20 beats per minute and limit themselves to around five breaths per minute in order to conserve energy, they can sometimes come out of a hibernation state to seek more food, get a drink, or excrete. So while most hibernators like to be snug and off radar for the duration, bats will need access to leave their hideaway. This means if you are making a mock bat cave or simply putting up some bat boxes, allow for a flight path in and out. Do check out Bat Conservation Ireland on Facebook or via

Bat boxes

The most important thing with bat boxes is a grooved interior to help the bats cling. You could use a palm router with a 1/4” straight bit to create horizontal grooves or you could upcycle decking boards, which are grooved on one side.

Bat boxes can be cubic or wedge-shaped but all require that the chamber have a bottom entrance (for bat preference access and makes it self-cleaning). One of the best and simplest designs is the Kent Bat Box.


You will require timber approx 20mm thick. In the following sizes (mm); Roof (A) 1 250 x 160 x 20, Back (B) 1 450 x 200 x 20, Centre (C) 1 330 x 200 x 20, Front (D) 1 210 x 200 x 20, Centre Rails (E) 2 330 x 20 x 20, Front Rails (F) 2 210 x 15 x 15. That said the only critical measurement is the access width of the crevices: needing to be 15mm-20mm. Assemble as shown above right.

Installing #batboxes - a home for farm wildlife. Lovely sunny day!

A post shared by Ailbhe Gerrard ( on

Frogs and toads

Frogs and toads also have this need on occasion to wake up from their hibernation and stock up on more food reserves. sometimes warming up over a mild winter keeps them awake — they are cold-blooded animals anyway so will match up to the ambient temperature but they are better able to slow heart rate and breathing when it’s proper cold out.

For the most part, both amphibian frogs and toads will lie dormant at the bottom of ponds, buried safe in the silt and sediment over winter, but a log pile or cairn of stones is a great option for those woken from their slumber or those preferring some land living.

Trug stops

There is a pond a few doors down and a canal nearby so I do get the occasional frog visitor over spring and summer — welcome for the quantities of slugs they ingest. As payback, I often leave a few trugs down by the log pile and compost heap at this time of the year — filled with water and some sediment and rock and topped with a tennis ball to bob about and prevent the surface freezing over. You could put a pond in or modify a tub from a skip or salvage yard.


Hedgehogs are rare in my parts — too many cars and foxes. But if you have them in your locality, they are a gardener’s friend (munching pests throughout the year) and so a nice safe place to bed down over winter is a good way of keeping them on the good side. They have the capacity to slow their heart from 190 beats per minute to around 20.

It will lowers its body temperature to around 10C, and minimise movement too. They like to go in deep so a large log pile or hedgehog box filled with dry leaves will see them right. Some hedgehogs make a beeline for your compost heap. No harm in tarping the top to keep it dry.

Log piles

Stacks of wood won’t be a problem after Storm Ophelia. Stack ’em high and wide at the base. You can push leaves and even soil through the upper tiers. Stability is key. The hogs will burrow their own way in and you can green roof the top as a nice feature and to weather proof it a bit more, or you can strap some tarp over the top to keep it dry.

Hedgehog homes

You can upcycle a wooden wine crate or a storage box to make a hedgehog haven. Simply cut an entrance approx 14cm sq and create a mound over the top to mimic a habitat and
weight it down for winter. You can more complex and make an entrance tunnel and an extra air vent. However adventurous you get, the essential element is waterproofing.


The biggest cancer killer will take your breath away

Hopefully she had an idea...

Power of the press: Meryl Streep and Tom Hanks discuss 'The Post'

More From The Irish Examiner