Nature 2003 October

An Oktoberfest of activity and colour

Despite the record-breaking weather of August with temperatures here reaching a steamy 36.3°C, by the time you read this I suspect autumn might already have signalled its arrival by way of morning mists, a severe frost or chill winds. However, as a testament to the enduring summer we have just experienced, I am sitting in the garden writing this article in the second week of September shaded by umbrella from the heat of the afternoon sun. The lawn resembles the Arizona dustbowl. Small Copper butterflies still abound, chasing each other at high speed and exercising their almost exclusive rights to the still resplendent blooms.

October signals the start of a month of rapid change for flora and fauna. On balmier days bees, of which the British Isles can boast over 250 species, over-wintering butterflies and other insects can be still seen on ivy, which flowers this month, stocking-up on the rich nectar, or sipping the juice oozing from overripe blackberries. Surprisingly, compared to most other years have you noticed the absence of wasps? The hot dry summer put paid to many garden pests and this shortage of flies and larvae in the latter part of summer will mean less food for the next generation of ‘wapses’. As an aside, this is a traditional English word for wasps and is also the origin of a field name in this parish ‘wapson’ or ‘wapoon’. To further support the ‘wasp thesis’ have you noticed the abundance of their fellow predators, the dragonflies, this year, which have been omnipresent as they patrol much further afield than normal from ponds, searching out their prey along our hedgerows and gardens? Ladybirds have suffered likewise. This absence of insect prey will also take its toll on birds that rely heavily on grubs for energy to keep warm on cold nights. The demise of slugs and worms will knock on to small mammals such as hedgehogs. A few judiciously placed hollow sticks in a dry place or a pile of logs will provide a refuge as well as a vital source of food for their predators.

Despite the reliance on calendars and clocks these days we seem still to be able to sense subtle changes in the seasons. A lively conversation with a local couple about the colour of the leaves on the beech trees around Cholesbury Camp and whether or not the way the trees shed their leaves informed us about the weather, started me thinking about how, at this time of year, each tree displays its own characteristic way of changing colour and shedding leaves. I think those of us lucky enough to live alongside trees are familiar with this annual parade and seem able without realising it to identify small variations in the timing and sequence from year to year. How each species of tree reacts in its own particular way is primarily down to shortening day length but is also affected by water availability, temperature and light. For example, most hawthorn trees will already be bereft of most of their by now shrivelled leaves and the race will be on to see whether it is the fieldfares and redwing arriving from north-east Europe or the thrushes and bullfinches that strip them of their ripe ‘haws’. The ash uniquely has a two-stage leaf-shedding approach triggered by the first hard frost of the season. Following such a cold snap it first looses just the leaves, leaving the stalks, which then fall a day or two later and temporarily giving the tree a frizzled look. Meanwhile the ash fruits or ‘keys’, at first green but later red-brown, are left dangling all through winter until spring. In contrast, horse chestnuts appear to have already anticipated the change and display a kaleidoscope of pastel hues.

Finally for the most unusual sight this month, although I guess gardeners and naturalists might disagree; look out for the antics of the daddy-long-legs (cranefly) behaving like an arthritic acrobat as they lay their eggs deep underground in your lawn with their oversized ovipositor. However if it has not rained by then and the ground is still more like Arizona than Hawridge at least spare a thought for them!