Nature Notebook

Dormouse © Danny Green

Snoozing through Winter

How often have you thought it would be nice to go to sleep in December and wake up when spring arrives...

KEEP UP TO DATE

Worcestershire Wildlife Trust @WorcsWT t worcestershirewildlifetrust G worcswildlifetrust.co.uk w It’s cold, it’s often damp and it’s sometimes snowy. Food is hard to come by and can be difficult to find. Insects are buried under a duvet of leaf litter or hidden tightly in crevices. Berries, ripe and juicy just a month or so ago, don’t last long as frosts take their toll and everything wants to eat them. Simply keeping warm takes huge amounts of energy. What better way to survive winter than to pretend it isn’t happening?

Hedgehogs, dormice and bats hibernate. A healthy summer dormouse weighs around 17g but as they ready themselves for the winter, that weight more than doubles to 35-40g. Like hedgehogs and bats, their body temperature and breathing rate slow significantly, helping them to survive on their fat stores alone. A hedgehog’s heart rate is usually between 200 and 280 beats a minute but in hibernation this drops to as low as five beats a minute. When to hibernate and wake up depends on both the species and the weather. Dormice can snooze from October to May whereas hedgehogs often don’t drift off until late November and wake up in March or April. Mild weather may cause them to wake up sooner; they’re able to forage for food but waking up often uses more energy than they can replace.

It’s not just mammals that enter a truly deep sleep. Perhaps you’re familiar with snakes and lizards disappearing during winter? This is called brumation, a dormant state that’s a reptilian version of the mammals’ hibernation. Common lizards, widespread but thinly distributed across Worcestershire, will have found hidden cavities between and under rocks or in hollow tree trunks. Like snakes, groups of lizards have been found hibernating together.

What about a hibernating bumblebee? As summer colonies come to an end, the newly emerging queens are the only ones to survive winter, ready to start new colonies when they wake in spring. To ensure they have enough energy for the big snooze, new queens drink plenty of nectar beforehand, which is why it’s important to have as many plants flowering through the year as possible. They’ll find somewhere safe – under the base of walls, in old mouse holes, under loose bark or at the top of northfacing banks in well-drained soils. Queen bumbles even have the ability to produce glycerol, which acts as an antifreeze to prevent ice crystals forming if the temperature drops below a certain point. As our winters are getting warmer, some bumblebee colonies are finding it easier to survive – look on heather, mahonia and other winter flowering plants and let us know if you see one www.worcswildlifetrust.co.uk/wildlife-sightings

Why not give dozing wildlife a helping hand? If you’ve got a garden, leave it alone until spring, all those fallen leaves and deadheads provide hiding places for lots of wildlife, from ladybirds to springtails. If you’re stuck for a gift idea, head to our website and take a look at our cards, calendars and gifts – every purchase helps the wildlife that’s snoozing through winter on our nature reserves www.worcswildlifetrust.co.uk/shop n Wendy Carter Worcestershire Wildlife Trust