Now that the days are getting shorter and colder, many animals will be settling down to hibernate.
Although we think of hibernation as a really long sleep, it’s not quite the same thing. Hibernating animals enter a state of torpor, with their metabolism, breathing and heartrate slowing down significantly. During hibernation, body temperature also drops. The result of these physiological changes is that the animal can stay alive while using very little energy – an effective survival technique during a time of year when natural food sources may be scarce or unavailable.
Slow worms and common lizards hibernate – these cold-blooded reptiles rely on warmth from the sun to heat their bodies and stay active. As the sun is often in short supply between October and March, it makes sense to hibernate through these colder months.
Many insects, including bumblebees and some butterflies, also enter a state of torpor to get through winter. Ladybirds seek out loose tree bark, hollow stems and other dry crevices to hibernate in. You may see them in your house – as temperatures drop they are tempted in by the warmth. They will also find sheltered spots in sheds, garages and greenhouses.
You can help all these creatures to make it through the harsh months of winter by providing suitable habitat.
Create piles of logs, rocks and leaves, and, where it’s safe to do so, leave larger fallen branches in situ. This will create habitats for all sorts of creatures, including slow worms and beetles, as the wood starts to rot.
To help hibernating insects, avoid tidying up the garden too much, and leave any dead stems in place until spring. The stems of teasels, sedums, and other perennials offer a safe hiding place, away from predators such as birds. As an added bonus, these attractive stems add interest to the garden in winter, especially when dusted with frost or snow.
Some animals, such as toads and badgers, don’t hibernate but will become much less active in winter, sleeping for long periods and only emerging to forage for food when the weather is milder. Toads often hunker down in compost heaps – so take care when turning compost, to avoid harming them.
Mammals in winter
While many mammals are less active during winter, there are only three UK mammals that truly hibernate: hedgehogs, bats and dormice.
Hedgehogs begin looking for a place to hibernate during October – but during mild winters they may still be active well into November. Hedgehogs like to spend the winter hidden away under log stacks, piles of branches or leaf litter, in compost heaps, or under garden sheds.
Although Bonfire Night is now behind us, many gardeners still build bonfires to dispose of garden debris. These are often built up over several days before burning, giving a hedgehog the chance to shelter unseen amongst the branches – it’s exactly the sort of habitat that hedgehogs look for when searching for a hibernation site.
If you must burn a bonfire, check it thoroughly for hiding creatures before lighting. A more wildlife-friendly solution is to create a pile of branches, sticks and leaves in a quiet corner. Not only will this provide an ideal habitat for hedgehogs, but frogs, toads, slow worms and all sorts of invertebrates may take up residence too.
There are 18 different species of bat in the UK, with 17 species breeding in this country. The tiny common pipistrelle, which weighs just 5g – that’s less than a £1 coin – is one of the UK’s most common bat species, and can be found in a wide range of habitats.
Bats hibernate between October and April, but when not hibernating they can be seen flitting along woodland paths across the Peak District, particularly where there’s a body of water such as a river, lake or stream nearby.
Many bats follow the same route as they forage for insects, so if you glimpse one, stand still – it will almost certainly come back into view.
To attract bats to your garden, encourage more insects by growing nectar-rich plants – especially night-scented blooms such as nicotiana, honeysuckle, jasmine and night-scented stock, as these will attract night-flying insects.
In autumn, bats seek out a cosy nook to hibernate in, looking for any space that remains dry and frost free. This is often in holes in mature trees, but they also roost in structures such as walls, barns or abandoned buildings.
The charismatic hazel dormouse is the UK’s only native dormouse species. These nocturnal animals live in trees, favouring mature hedgerows and woodland habitat – especially areas of new tree growth resulting from woodland management such as coppicing.
Dormice hibernate from October to April, finding a cosy place at ground level to bed down in, often at the base of trees. Before hibernating, they need to fatten themselves up, feasting on berries and hazelnuts to increase their body weight from around 20g to as much as 35g. In spring and summer, they eat insects and the flowers from oak, hawthorn, honeysuckle and bramble.
Sadly, dormice are in trouble. The newly published State of Britain’s Dormice 2023 report, by People’s Trust for Endangered Species (PTES), has found that hazel dormice have declined by a staggering 70% since 2000. And since Victorian times they have been lost from 20 English counties.
These catastrophic declines are largely due to the loss and poor management of woodland and hedgerow habitat, with climate change also taking its toll.
However, there is hope for these enigmatic endangered animals. The PTES dormouse reintroduction programme, alongside other conservation and rewilding projects, is helping dormice populations to re-establish in suitable areas across the country.
This includes the successful introduction earlier this year of 38 dormice in Derbyshire, at the National Trust’s Calke Abbey estate. Well-managed woodlands and hedgerows on the estate provide an ideal habitat for the animals – and reintroductions such as these are helping to ensure a future for the species.
For more information about dormice, and how to help – including by supporting PTES – visit www.ptes.org/ campaigns/dormice.