A regular column from Lincolnshire Wildlife Trust’s Rachel Shaw.
We are now entering the darkest and coldest time of year.
Many birds have already left our shores heading for the warmth of southern Europe and Africa, and the wildlife that stays has been preparing for the season ahead.
Many mammals grow thicker fur and will sleep through the coldest of days, emerging only on mild days to search for food.
Over the autumn grey squirrels have been collecting nuts and seeds and burying them in hiding places or ‘caches’.
Their spatial memory and acute sense of smell helps them find the caches weeks or even months later.
However, many remain uneaten, allowing the seeds and nuts to grow and helping to disperse the trees through the woodland.
Hedgehogs eat slugs, earthworms and beetles, and in cold weather they would spend more energy looking for food than they would gain from what they find.
The solution is to hibernate.
Hibernation is different to sleeping. When animals hibernate their bodies enter a state of torpor with a reduced body temperature and metabolic rate, slower breathing and heart rate. This allows them to save energy that would normally be used to maintain a high body temperature.
Before entering hibernation, they must have sufficient fat stores to survive through the winter months and when they wake in the spring, they will need to find food quickly to replenish the weight they have lost.
Some small birds, such as blue and great tits, join together in flocks to forage together for the scarce food resources.
They will also huddle together overnight to benefit from each other’s heat, sometimes in garden nest boxes. The record number of wrens seen roosting together in one box is 63!
The next generation of many insects and other invertebrates are buried in soil or behind loose bark of trees as eggs, larvae or pupae, but some overwinter as adults.
Snails clamp themselves tightly to tree trunks above the reach of ground frost.
Ladybirds huddle together, sometimes in very large numbers, under tree bark, inside hollow plant stems and even in window frames.
Red admiral and small tortoiseshell butterflies find shelter in frost-free places such as the natural hollows and crevices of trees and in sheds and outhouses.
Winter’s long sleep will end as soon as March for some animals; spring is almost here.