As winter strikes, what strategies have our wildlife developed to help them survive these harsher months
December is the first month of winter. The days are short, the sun is low in the sky and temperatures are slowly falling. For virtually all forms of wildlife food is now becoming difficult to obtain. There are far fewer insects, almost no flowers with nectar or pollen, and many of the young mammals born in the heady, food-rich days of summer that would have been food for owls and kestrels, have starved or been eaten already.
Winter is tough, a season without compromise to be endured or avoided. So how have different forms of wildlife evolved varying strategies to cope with this season?
Birds have only one choice really – should I stay or should I go? It’s what we term migration, but the distances can vary widely. Curlews and merlins, for example, will have left our now inhospitable moors and headed out to the British coast where the ‘storage heater’ effect of the sea keeps the shore warm and food-rich throughout winter.
Some smaller birds such as tits, nuthatches and tree creepers tend to stay. Others, such as pied flycatchers, have put on weight in the autumn and leave on perilous, long journeys across the deserts of Africa to more southern countries where the sun shines and there are lots of insects.
For those that stay, some change their food source to a more convenient, plentiful one. Insects are now in very short supply so birds like the nuthatch and great-spotted woodpecker switch their diet to one containing more plant food, such as nuts. Other species, such as the tree creeper – a small, mouse-like, brown bird that doesn’t have the thicker bill of the nuthatch to allow it to exploit nuts – will stick with insects but now rely on trying to find any that are hibernating in buds and in cracks in the bark of trees.
In many ways, if you want to see winter birds December is one of the best months to go out bird watching in any of Derbyshire’s woodlands. True it may be cold, even a little dreary, but the absence of leaves makes spotting the birds easier and they are far more active as they have so few daylight hours in which to stock up on energy to see them through the following night.
Not all our birds leave our windswept moors. Red grouse and ravens tough it out until the warmer days of spring. In fact, unless it’s an incredibly hard winter, both almost seem to thrive.
For red grouse there is no food shortage, the moor is literally covered with heather. It might not be at its most nutritious, but it certainly won’t run out.
Ravens have successfully re-colonised most of Derbyshire over the last 30 years and it’s rare now not to hear that basal cronk as a pair play on the icy wind over one of our limestone quarries or dark moorland. Ravens are arguably the most intelligent British bird and they are masters at survival, taking every opportunity that falls their way. Their diet is varied and winter can actually be a season of plenty as hares and sheep succumb to the cold of night.
Mammals’ strategies to survive the winter months are more varied than birds’ but, because we are an island, long-distance migration is not really on the cards. And even if it was, the physical barriers of road, town, river and hill would be difficult to navigate on a regular and safe basis. However, a few mammals have one incredibly neat strategy that birds have never evolved – hibernation. In Derbyshire there are actually fewer mammals that hibernate than many people think. Our only true hibernators are dormice (though it is unclear if they are still present in the county), hedgehogs and bats. All other mammals remain active throughout winter, though you may see them far less.
Rabbits, brown and mountain hares don’t stock food like squirrels so remain active throughout the winter. Grey squirrels (we don’t have any reds left unfortunately), can cache food in the autumn but if acorns are in short supply they will have little in the larder so will be more active than normal and switch to eating more buds and, if desperate, debarking trees – as do rabbits when they are starving.
Even in snowy weather, badgers will still venture out in search of food. In my garden I have a lone male badger that visits every second or third night right through winter and – as I do for the birds – I leave him a handful of peanuts every night.
December can seem a bleak month to watch wildlife but you should never consider it so. On our moors you can watch white mountain hares and red grouse with comparative ease, and in areas around Big Moor you should be able to spot one of our increasing herds of red deer. In woodlands bird song may be at a premium but the small birds that decided to tough it out are still here – nuthatches, tree creepers, blue, great and cole tits and chaffinches, and on our streams and rivers dippers still hunt for river bed invertebrates, while ducks such as mandarins are always a delight to spot. Good winter watching!
