Surviving the winter – as snug as a bug

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Making a hibernaculum to help keep a frog snug during the winter
Making a hibernaculum to help keep a frog snug during the winter

With temperatures dropping and winter now upon us it’s important to think about how animals cope in the winter and how we can help provide over-wintering habitats. No matter how big or small your school grounds or back garden, you can create features to help shelter and protect wildlife through the cold months. So if you’re wondering what do with piles of fallen leaves and pruned hedge clipping then read on for some great activity ideas to learn about and help animals in the winter.

Animals have differing habitat requirements during the winter depending upon their levels of activity and availability of food. They can survive in one of three ways: hibernate, remain active or migrate.

There are different types of hibernation. Mammals such as hedgehogs, bats and dormice are true hibernators; their heart beats slow down, their bodies cool down and they remain in this state throughout the winter.

Other mammals enter a state of torpor (light hibernation) such as badgers. They become inactive and sleep more deeply for part of the winter to conserve energy, but their body temperature remains higher than those of hibernators. They can awaken during mild weather and eat stored food.

As temperatures drop cold blooded amphibians and reptiles also slow down their activity and enter a state of semi-dormancy called brumation. They cannot raise their body temperature independently of external conditions, so they overwinter and do not appear again until spring. Some frogs and newts may spend winter in the muddy bottom of ponds.

Insect hibernation is called diapause and as temperatures drop they suspend their development and remain inactive burrowed in the ground or a tree, or grouped together in crevices.

However, for resident birds that do not migrate and most common among mammals is to stay active during the winter. So as we get cosy for the winter, spare a thought for our feathered and furry friends by helping to feed them or by creating some cosy, snug shelters.

Activities and investigations:

Habitat survey: Carry out a survey to see how friendly your outdoor space is for visiting and over-wintering wildlife. It’s a good time to clean out bird boxes as these can provide shelter for birds in the winter. Identify sites where features such as those listed below could be added:

  • Compost heap: A large, open pile using slatted wood makes is the most wildlife friendly option. Reptiles and amphibians choose frost free locations to spend the winter and will happily hide away in a compost heap. Don’t turn the heap until early spring as hedgehogs will also nest and hibernate here.
  • Leaf piles: Simply sweep fallen leaves under a hedge. Hedgehog nests are usually found at the base of hedges or bramble thickets. Alternatively make a wire cage using wooden posts and chicken wire to make a leaf mould tower. Hedge trimmings stacked and tied into a pyramid with leaves inside also work well. This will provide short term shelter for amphibians and many invertebrate species.
  • Mini-hibernaculum: This is a shelter where amphibians and reptiles can see out the winter months. Half bury clay pots and fill with a little soil, leaves and wood chips. Cover with excavated soil and hedge trimmings. Make sure to locate where soil drains well and is burrowed below the frost line. This also provides shelter for hibernating insects.
  • Log pile: Position logs in partial to full shade for damp loving amphibians. Bury the bottom layer if possible. Frogs and toads over winter in gardens and if disturbed these are suitable places to relocate them.

Bird tables:  Regular feeding throughout the year, especially in winter, will attract a wider variety of bird species to watch and study.  There are many types of feeders that can be brought or made. Design and make your own bird food recipes and record which recipes attract which species. Suet and seed mixture pushed into pine cones are a favourite.  Don’t forget to provide fresh water in a shallow bowl.

Hot potato hedgehogs: Hedgehogs are on the UK list of 10 most endangered species. Check out http://ptes.org/campaigns/hedgehogs/ to find out why and how you can help. A group discussion can then lead onto a fun investigation about hibernation.  Working in groups they have to predict from a range of materials which would be best to keep a hedgehog warm and best place in the grounds for a hedgehog to hibernate. Groups then build a home taking a temperature reading of a pre-heated potato (standing in for the hedgehog!) before and after. Whose hedgehog kept the warmest, what materials were the best to use?