Snow is falling, all around me. It is clear that winter is well underway - it has been getting gradually colder (just ask my toes) and the days are now dark by four'o'clock. The forest, hills and bogs of Abernethy are covered in white snow, like the icing on a giant Christmas cake. Even Loch Garten is white, having frozen over and received a dusting of the white stuff, and we're all dreaming of a white Christmas. There's a definite feeling that wildlife has now wound down for the winter, settling itself in for the long cold months ahead. In my last blog, I talked of the many broad-leaf trees throughout the forest that were displaying their autumnal colours like myriad paint explosions splattered among the pines. These trees are now completely bare and their leafless, spindly forms seem to shrink back into the forest, hiding away from the Scottish weather. It's undoubtedly a tough time. Many plants go into this dormant state over winter, losing their leaves and saving energy for the arrival of spring. Animals have it slightly harder, needing to keep themselves fed, warm and protected from predators during a period when food, warmth and protection are hard to come by! Those animals local to Loch Garten have a number of different tactics for tackling the winter hardship, from facing it head on to escaping it completely!
Frozen Loch Garten. Image by Chris Tilbury.
Many birds will avoid the problems of a cold winter by simply leaving Scotland and flying far, far away to find a slightly more agreeable climate. They have no time for snow covered Christmas trees or Frosty the Snowman. Do they know it's Christmas time at all? Look at our brilliant ospreys - long before the first frost, they up sticks and head south, looking for sun, sea and sangria (well, maybe just the first two!). This is also true of many smaller species such as redstarts, swallows and warblers who make epic migrations of thousands of miles chasing the summer sun. In many ways this is a great tactic as food is plentiful all year round and frost and snow are unknown concepts, however, the migration itself is a gruelling feat. Redstarts, for example, are small, robin-sized birds that weigh less than an "AA" battery. They fly to and from Africa every year, a round trip of over 7000 miles, facing strong winds, storms and fog, not to mention the disgusting threat posed by human hunters. The energy needed to make this trip is a big price to pay and many birds don't survive, even relatively big birds, such as ospreys.
For those birds that don't or can't migrate, they must face winter head on, but there are a few different approaches to this. Many birds that might be seen alone for much of the year, such as wrens, now join together in loose flocks. This increases the chances of finding a food source and means individuals can huddle together during cold weather to keep each other warm. Treecreepers are also known to adopt this practice. Many birds, including jays, will hoard food during the summer and autumn, when supplies are plentiful, hiding berries, nuts and seeds in tree cavities. This ensures that when winter hits they have a ready made buffet available!
Jays will hoard food for the winter but will also make the most of gardens. Image by Chris Gomersall (rspb-images.com)
It's also worth remembering that there are many birds that come to Scotland for the winter! I know this might be hard to believe sometimes, but there are many places that become much, much colder than the Highlands! Thousands of geese and swans arrive from the Arctic and Greenland, escaping seriously snowy winter conditions, and we also see many thrushes, redwings, fieldfares and waxwings arrive from Scandinavia and Russia, hoping to feast on Rowan berries and other local delights! Often, if you see one of these birds during cold weather, you'll notice that they look much fatter than normal, despite the lack of available food. They haven't, I promise, been eating too many mince pies, but will have simply fluffed up their feathers, especially the soft, insulating down, which traps air and keeps them nice and toasty. It's a bit like walking around with a big, down duvet wrapped around you all winter! Genius. Actually, I might try pitching that as RSPB uniform...
Birds such as robins fluff up their feathers to keep warm in winter. Image by Ben Andrew (rspb-images.com)
But, of course, it's not just birds that make their home at Loch Garten. Anyone who visited this summer will almost certainly have caught a glimpse of some of our delightful field voles. There were hundreds around this summer, normally seen around the bird feeders as they dashed back and forth collecting the dropped seed. It would be easy to assume these voles hibernate all winter, cuddling up in a warm little burrow to emerge safely in the spring. However, actually voles tend to remain fairly active throughout winter, albeit with some minor alterations to their summer habits. Whereas during the warmer months voles will eat seeds, berries and fresh vegetation, such items just aren't available in winter, meaning some clever compromise is needed. Voles will collect and store grass over the summer, meaning they have some vegetation available, and will also adapt to eat a variety of other materials, including treats such as tree bark. That's good eatin'! Now, you might think that when snow falls and creates a freezing, white blanket throughout the forest, small animals like voles stand no chance. However, they actually thrive in these conditions. They burrow underneath the snow, making a network of interlinking tunnels which they use to move around. Far from being cold, these tunnels are actually well insulated by the snow and tend to be a few degrees warmer than the air temperature, allowing the voles to live quite comfortably. They can also move freely between food sources and sleeping burrows, with the hidden tunnels providing a good level of protection from predators such as owls and stoats, with the voles simply having a wonderful Christmas time.
Red squirrels are another animal often thought to hibernate throughout the winter. They are actually quite happy to be walking in a winter wonderland and become even more regular visitors to garden feeders (particularly peanuts). On particularly cold, snowy or windy days, they will tend to hole up in their dreys, protecting themselves from the wintry weather. This is where that big, bushy tail comes in handy, providing a cosy blanket to snuggle under and often more than one squirrel will share dreys to ensure even more warmth. Red squirrels also grow long ear tufts over winter which help by reducing heat loss from the blood through the thin ear membrane!
Red squirrels grow their own ear muffs in winter!
Amphibians such as frogs and toads see out the winter in what is known as a state of torpor, slowing down their metabolic rate to enable survival during periods without food. Frogs will sit at the bottom of ponds or in mud patches, escaping the freezing air temperature above. They are able to survive by accessing the oxygen dissolved in the water around them. Toads, more land dwelling than frogs, will find a sheltered crevice underneath a (Jingle Bell) rock or leaf pile, nicely insulated from the cold. This process differs from hibernation because amphibians will re-animate during spells of warmer weather rather than remaining inactive for the entire winter. This allows them to make the most of opportunities to find food and means they don't have to build up their fat reserves during the summer and autumn.
Toads find a protected spot to get torporific!
But what about the invertebrates? The millions of midges, scores of spiders and armies of ants all have strategies to survive the Scottish winter. Butterflies, for example, will look for a dry, safe spot to hibernate and you'll often come across them in your garden shed or, in my case, bathroom cupboard. If you do find a hibernating butterfly, the best thing to do is leave it where it is or, if that's not possible, carefully move it to somewhere dry and warm-ish, where it can see out the rest of the winter. Everyone's favourite insect, the midge, survives winter by...er...well, actually,most midges won't survive the cold winter temperatures. Some will find shelter among the grass and ground vegetation but generally they ensure the survival of their species by laying their eggs in ponds and lochs before the first frosts. These eggs are incredibly resilient and well insulated and are usually left deep enough in the water to escape the top layer that tends to freeze. Wood ants build incredible nests in the forest, using pine needles and other natural materials to construct huge piles that can each house millions of ants. These nests are like ice bergs, however, with much of the layout actually hidden underground. During the autumn, the queen will stop laying eggs and therefore the colony stops growing. As winter draws on, many of the ants in a colony will die, with only the queen and a number of the workers surviving by keeping to the lower, warmer sections of the nest. When spring arrives, the workers begin foraging once again and the queen begins laying eggs once more.
Wood ants head underground for the winter. Image by Jackie cooper (rspb-images.com).
So a few strategies there for surviving winter. The last creature I'll tell you about is the very rare (but incredibly beautiful) Visitor Experience Manager. Known for their superb sense of humour and overall awesome-ness, during the winter you'll most likely find them in front of a roaring log-burning stove, clutching a mug of mulled wine and chomping roasted brussel sprouts (definitely the best method for cooking them, by the way). Contrary to many animals, VEM's will often emerge in the spring with considerably more body fat than before...
That's it from me for now. Merry Christmas to you all from everyone at RSPB Abernethy. I hope you have a lovely festive period and an unforgettable Hogmanay. See you all in 2018!
Father Chris-tmas x