Nature 2018 October

Autumn in all five senses

According to John Keats, autumn is a “season of mists and mellow fruitfulness”. The fruitfulness the poet had in mind was produce from the cottage garden or farm such as orchard grown apples, cereals stored in the granary or ‘gourds’ (as he calls them) by which he meant those soft-skin varieties like pumpkins and squashes.

Further afield he considered fair game anything from nature’s larder, from hazel nuts foraged from the hedgerow to poppies, of which he acknowledges the narcotic properties of the seeds scattered within the furrows of ploughed fields. So I have sketched out my instant thoughts on how the autumn season affects the senses, whether those are our own, or those of the wildlife around us.

Sight – Visual signs of the autumn season getting underway are often indiscernible, fleeting or clandestine. On warm evenings, as heat escapes from the ground, insects float upwards on the air currents. This is likely to attract, at first, just small gatherings of swallows swooping low overhead. Within days the aggregations become larger and more persistent. Suddenly the swallows depart and their sudden and total absence is as much a signal that autumn is approaching as was their presence. Now take leaf fall. In the Chilterns we are lucky to enjoy a wide variety of woodland, hedgerow and solitary tree species. Whilst our woodlands may not be able to mirror the vast expanse of magnificent crimson reds and burnt oranges of the New England Fall, in a good year the cascade of hues transitioning over several weeks from light green to chestnut brown is a match for any north American display.

Smell – There are brief occasions throughout any year when you don’t need to rely on your eyes but instead on your sense of smell to identify what season it is. A sniff of wild garlic would tell you it is early spring. Later in this season both hawthorn and elderflower can be overwhelming. For some reason I associate the smell of foxes with cold mornings and evenings in winter. The essence of wild honeysuckle on a summer’s evening can be almost intoxicating. But what about the autumn? Thinking back to previous years for me the redolent essence of the autumn is the musty effluence of some fungi. Two identifiable to the nose and also visually are the puffball and the stinkhorn. Each enjoy the rich compost formed beneath the leaf litter. Consequently, without the profusion of their often overpowering perfumes, they would otherwise be passed undiscovered. The uninviting smell emanating from the common puffball is caused by the dispersal of spores when the puffball is rained upon or consumed by animals. Prior to spore development the common puffball is, in fact, edible and considered a delicacy in some places. Similarly, the common stinkhorn can be consumed (not recommended that you try it though) when it first emerges from underground. However, as it grows it becomes poisonous and distinctly unattractive and unpleasant to smell. Insects are readily attracted by the odour and by eating the fleshy fruiting body the stinkhorn’s spores are dispersed.

Taste – Autumn is available in many flavours. Blackberries provide a vital source of sugars for late season insects like wasps and flies. Because of this a number of species of arachnids, such as the orb spider, make their home and set their silken traps adjacent to the overweight stalks of fruit and make a killing on the insects they entangle. Overripe elderberries normally survive into October and become a favourite for woodpigeons. Hanging perilously from the inflorescences the pigeons can become intoxicated. In this drunken state they will be increasingly sluggish and susceptible to predation by sparrowhawks. Because of their corpulent physique these heavyweight birds are inevitably slow-moving and an obvious target for not just the sparrowhawk but also the occasional fox. Despite this, through eon-old struggles to survive, woodpigeons have in fact evolved a strategy to maximise their chances to survive such surprise attacks. Unlike most other birds, certainly those of a similar bulk, when woodpigeons are startled they take off vertically. An orientation which cannot be simulated by most other birds, even the sparrowhawk, let alone old ‘Reynard’.

Sound – Back in November 2003 in my Nature Notes I made reference to a little-known ghost story centring on these parts. It is known as The Screaming Pigs of Cholesbury recounted by local historian John Pilgrim. In the briefest of words, the story is told of… ”strange ‘unearthly noises’ emanating from Cholesbury Camp and the reluctance of even the most fearless of the men of the village to enter the Hillfort after dusk”. The supposed origin of these disturbing sounds is the echoes of pigs being slaughtered by pagan inhabitants of the Camp. I suspect most of us have been spooked by the nocturnal shrieks of foxes and awoken at an unearthly hour by the incessant barking of muntjac. Distressing as they both sound it is the inevitable result each autumn when there is romance in the air! For foxes it is an intimate affair whilst for muntjac, who breed all year round, it is usually a male deer staking out its territory, telling the females he is ‘on station’, or chasing off another male, or just sounding a nervous alarm if disturbed.

Touch – So delicate and susceptible to damage when there is any pollution in the air, lichens have been used as a barometer to measure the presence of a whole range of such pollutants; noxious gases, rainwater acidity, and airborne particulates. The clean air we are lucky to breathe up here, 600 feet in the Chilterns, provides an atmosphere conducive to a wide range of lichen varieties. This variety means we can find lichens with many textures which feel so different to the touch. At this time of year these sensations can be enhanced by the emergence of fruiting bodies which in time will release spores. Almost any surface that has been in situ and stable for some time can provide the substrate to host one or more varieties of lichen: for example, slate and tile roofs, trees and bushes, stone walls and gravestones. These habitats are also rich in micro fauna, such as beetles, mites and woodlice and consequently are also excellent hunting grounds for small insectivorous birds, animals such as shrews, wasps and ants.

So autumn can be a delight for the senses. When out and about, try and experience the season using all of them!