Nature 2008 December

Three of a kind

So an unexpected cold easterly wind unusually brought freezing rain and snow at the end of October. For any self-respecting wildlife, which was hoping for a prolonged warm spell, that snap has signalled winter is on the way. For migrating birds such as geese and swans, which had been reported delaying their journeys from Scandinavia and beyond, this was sufficient to trigger the packing of bags for the flight south. Last winter was much wetter, warmer and generally unsettled than normal. This year there is expected to be a return to cooler, but slightly dryer conditions. With the water table remaining high, footpaths and bridleways will remain ‘claggy’ and waterlogged.

Three birds which make their presence known, even in the heart of winter, are thrush, great tit and robin. Song thrushes are, in January, one of the few to provide a musical tune at either end of bleaker days. Silent since the summer, Mavis (as it is colloquially known) has a distinctive and mellifluous sound, heard as night turns to day and day to night, singing for up to an hour. Each stanza starts with a sound not unlike “January joy”. Listen out for a particular bird’s unique signature notes which typically will be repeated three times during its repertoire of resonant reprises. Their smaller relative, the mistle thrush, has an altogether more random song, a kind of improvised jazz but more persistent when the weather is inclement for which they have gained the name ‘storm cocks’. Meanwhile, during the short days, great tits launch into song, a triplet of “teacher, teacher, teacher” high up in a barebranched tree. Ironically, during the season of good will, the iconic robin is at its most fierce, defending its territory and chasing off every red-breasted opportunist that dares to make an appearance with an equally strident vibrato call.

Three things to look out for! First, during October/November, this part of the Chilterns has been host to a festival of kites displaying over the open fields at Braziers End and St Leonards. Several sightings have been made, indicating this may continue to be a regular feature in this area. Such mass sightings signify that the birds are supplementing their scavenging with food specially provided for them. Second, winter parasites. How do you get rid of those irritating fleas, ticks and mites from your feathers? In a dry summer, a dust bath can do the trick but in winter what options do you have? Well try out what crows can be seen doing this time of year by using the smoke from chimneys. It can make the eyes water but you should be able to stick it out longer than your unwelcome visitors.

Third, one of the earliest signs that the season is on the turn are the catkins of hazel, in clusters of three, slender and brown at first but early January sees them lighten and turn from pale to brimstone yellow.

Every three years or so we are invaded by a third and most colourful Scandinavian visitor whose sole purpose in visiting seems to be food shopping. Waxwings, with their sleek beige coats overlain with russet brown and with black, yellow and white highlights, are particularly partial to the red and orange berries of cotoneaster, pyracantha and vibernum bushes that adorn supermarket car parks. They start with the north-east coastal outlets but as the weather hardens they move south and west so a cold snap could bring them to a local Tesco, Waitrose or Sainsbury (with the obvious bonus of nectar points!) or to your garden.

A triplet of trees to look up to: Sycamores with the most ungainly arrangement of branches of all our local trees hold the key. The last bunches of bedraggled, winged fruit (keys) hang waiting to be wrenched away and assisted on their journey by just one more gust. Later on, the first pale green buds of the new season are visible, having shed their waxy scales. Also making a show; the more subdued spear-shaped beech buds remain tightly shut but have turned a dark purple and now stand out aside the rusty leaves retained on the tree to protect these more delicate buds. Oak leaves may remain into December in more sheltered spots, if the weather permits. On bright days the leaves appear pink. This is partly due to the remaining pigments gradually being milked of their remaining goodness as the tree withdraws vital elements into its sap. However, the colour is sometimes augmented by disc-shaped protuberances, containing the larval stage of the spangled gall wasp. The tree produces these structures in an attempt to isolate itself from the invader, but provides just the protection the larva needs to mature into an adult.

Three so-called cold-blooded animals, snails, newts and snakes are forced into hibernation from now onwards. It is not just the temperature, but the lack of accessible water when temperatures fall to around zero or below. In the invertebrate world there is often a correlation between speed and longevity. Take the garden snail, which can apparently travel at up to 0.03mph or about 2 ’ 6” per minute. Life expectancy is 10 years in captivity, but two years in the wild. For half that time it will be totally inactive, living within its shell and sealed from the outside world by a bung of mucus called an epiphragm. Before closing the door on winter the snail will have perhaps followed the trail laid down by other snails down an old mouse hole or under a stone.

The three species of newt: smooth, palmate and great-crested, can also live for up to a decade. From late November they hibernate within stone walls, piles of logs or occasionally within the mud of their breeding ponds, until emerging in late February or March. They can travel up to two miles to find a suitable breeding pond.

Each of the three British snakes: grass, smooth and adder hibernate and choose regular sites known as hibernacula. Typical are old rabbit scrapes. Unlike the previous examples, snakes have already found a safe haven by now. The young of grass snakes hatch from eggs in October and immediately seek refuge for the winter. Snakes will only emerge when temperatures have maintained certain levels over a number of days and will quickly seek sunny areas in which to bask and warm up. Much of their hunting is done from water in which they are most agile swimmers.

Three books of a kind for Christmas now: ‘Food for Free’ by Richard Mabey is full of interesting stories, superstition and use by man of plants we can forage for today. ‘Notes From Walnut Tree Farm’ and ‘Wildwood, a Journey Through Trees’ are both by the late Roger Deakin. From a quick browse, they are full of brilliant observations and writings on everyday life in the countryside and the wider world.