Nature’s weather forecasters

WHILST we may have sophisticated instruments, including satellite information, and high-tech computers to provide meteorologists we see on TV to give us with a three- to five-day weather forecast, animals, insects, birds and plants are actually very good short-term forecasters. This week I will give selected examples of how flora and fauna presage atmospheric conditions.

Flora

Flowers tend to perform short-term weather forecasting by opening and shutting their petals but this can be unreliable. Certainly they do like getting their pollen wet. In the UK, the Scarlet Pimpernel (Anagallis arvensis), which is found in hedgerows, closes its petals before rain arrives. Locally, it is known as the ‘shepherd’s weatherglass’. The Common Plantain, normally found in summer time with swollen heads, closes its anthers on dewy nights or upon sensing rain to protect its pollen.

Warmth can also be sensed by flowers. The passage of an overhead cloud and the shadow cast sees very sensitive flowers, such as crocuses and tulips, close up. A crocus can sense a mere fall in temperature of 0.5 degrees Celsius. Springtime in the UK, sees the first flowers bloom as they trap heat almost like minute solar panels. These solar-heated flowers attract insects which, in turn, act as pollinators. Dryas octopetala flowers swivel by day, like satellite dishes, following the course of the overhead sun. Thus, these flowers are kept a few degrees warmer than their surrounding atmosphere and, moreover, attract pollinating insects.

Pine cones from coniferous trees are pretty reliable indicators of wet or fine weather. When the weather turns dry, the fibres, behind their scales, open and release their seeds. Some species of pine explode their seeds with whip-like cracks.

When humid weather is approaching, the fibres bend inwards and close the scales tight. Recently, a UK textile scientist and designer produced a fabric to reverse pine cones activities. Her newly-designed fabric opens minute pores to allow the textile to breathe in wet and humid conditions, thus releasing moisture from the wearer of a garment. In dry weather, the pores close and provide insulation. In the near future this fabric will, no doubt, be marketed by leisure wear companies.

Bird indicators

When seagulls come far inland from the coast usually a storm is on its way. Today, with inland infill rubbish dumps where seagulls can be seen scavenging, this may not be quite true. However, fishermen still believe that when the most aptly named sea bird, the Storm Petrel, flies close to the shore, stormy weather will ensue. Very near my house is a rookery, home to at least 250 rooks. As these jet black birds return to their nests each evening, if flying low with tumbling around in the sky, I know that rain is on its way. If flying high at dusk, the next day will be fine.

Migratory African birds to the UK in summertime, such as swifts and swallows, both of which build mud pellet nests on the eaves of my house, are my best indicators of changing weather. If swooping high in the sky, in collecting insects for their hatched babies feed, the weather will be fine for a while. If swooping low over the meadows, I know that rain is coming for the insects are seeking shelter under vegetation.

Frogs

Do we all hear the frogs croaking in the roadside drains in Kuching? Usually, the wet season is on us and, even after a brief dry break in the weather, the frogs are useful indicators of more wet weather ahead. It’s mating season for these amphibians. I just wonder if crocodiles are weather forecasters for I know little about their choice of habitat or their movements in response to weather change. Many years ago, I stayed in the foothills of Mount Kenya and heard the repeated croaking of frogs by day. This frog species, known as the Mountain frog (Rana wittei) croaks with fury by day when temperatures are above 5 degrees Celsius but on cold nights, with near freezing temperatures, it cannot be heard.

Insects

Butterflies are sun-lovers extraordinaire, for they depend upon heat to fly. Their muscles do not work unless they are warm enough. One species in the UK, the Orange Tip, living in woodland glades, immediately closes up its wings when a cloud blankets out the sun. No doubt they are true indicators of impending rain.

Spiders are particularly sensitive to wet weather and fearful of raindrops. Just before the first drops of rain fall, they cut out sections of their delicately woven webs and collapse them. Some even climb down to the bottom of their webs and stretch out their forelegs to act as gutters to quickly drain water away. In fine weather, they fly around the sky on gossamer. On some sunny days, I have seen spiders ‘ballooning’ in light wind conditions as they fly through the air to new nesting places. Their attached gossamer acts like a parachute.

Bees outshine all insects for their weather forecasting capabilities. For them to leave their hives the outside temperature needs to be above 20 degrees Celsius, with low relative humidity and wind speeds of less than 6.5km per hour. Low temperatures, little sunshine or high winds, discourage them from leaving their hives and thus honey production is low. They sense that flowers and flowering shrubs will not release their petals to reveal their nectar traps. A sudden darkening of the skies, indicating an impending downpour of rain, sees bees zooming back to their hives. Beekeepers maintain that bees are sensitive to a build-up of static electricity in the air and become very bad-tempered. Thus, beekeepers avoid their hives when thunderstorms are imminent.

There is no doubt that all living creatures great or small have inbuilt weather prediction systems. I have dealt mainly on European species of weather indicators for there is much truth in folklore anywhere in the world. There must be scores of such present and past observations on nature’s responses to changing local weather patterns that have never been recorded.

There must very many indigenous people in Borneo who have had such animal, bird or insect observations passed down from one generation to another.

Meteorologists would welcome such thoughts into their weather knowledge.

I well remember my Welsh mother’s occasional sayings on the day of the family clothes wash.

The clothes were hanging from two clothes lines – well before the advent of tumble dryers. Her cry was simply, “Help me get the washing in before it pelts with rain.” How did she know that rain was imminent in the middle of summer? Beata had noticed that the bees were no longer buzzing around the fruit trees and flowers in our garden, the birds were no longer singing, the skies had darkened and our pet rabbit had run into his hutch.

We all have much to learn from our personal observations, not only of cloud patterns and TV forecasts, but to simply look at and observe the behaviour of the fauna and flora around us in our daily lives.