IT’S A national pastime to complain about the weather and if we have another hard winter we will grumble on about the frost, the snow and the disruption caused to our lives.
However, most of us have more than adequate food, shelter and warmth to see us through, so spare a thought for our smallest birds and mammals in their daily struggle for survival.
Our lively goldcrests are the UK’s smallest birds. They are rounded bundles of feathers with an individual having the weight of a 5p coin and measuring only 9cm. Their main habitat is the higher reaches of conifers but you will also find them in mixed woodland.
Because they are so small with a high metabolic rate, they are constantly flitting about during daylight hours in winter, foraging and feeding. On a cold night they can lose a fifth of their body weight but can survive in temperatures up to –20˚C. They will huddle together at night roosts to help retain body heat but mortality can be high during prolonged low temperatures.
The difference between life and death is therefore an adequate daily diet which sees them through until the following morning. Their slim, sharp bills will search out tiny insects 2-3mm in size. These will include aphids, beetles, flies, insect eggs, spiders and springtails. Sometimes an insect is snatched from a spider’s web. Springtails are wingless, primitive insects which have bristles under their body which enables them to jump about and they are major prey for goldcrests in winter.
These birds have a number of different faint, high pitched calls and it is often these calls that make you aware of their presence in the vicinity. However, you may well have to look around a while before you see one. Human presence does not easily disturb them and they are a delight to watch at close quarters.
Breeding pairs in the UK often exceed half a million. These are mainly resident but birds from the continent migrate to our milder climate in winter. Amazingly they can travel up to 200km in a single day. In winter these continental arrivals can swell our goldcrest population to 4 million.
Pygmy shrews are one of our smallest mammals weighing in at 3-7g. Like goldcrests they are insectivores living on worms, slugs, beetles and other small insects. Heat loss is a big problem because their bodies are so small.
They therefore hunt at a frantic pace for two-hour periods followed by a quick sleep, and then the feeding frenzy starts again. If they had a day without food in winter they would simply die. As they favour deep vegetation we don’t often see them. Predators do not enjoy their taste, the fox and kestrel much preferring a juicy vole.
Many of our birds and mammals will succumb to the rigours of winter, but nature is resilient. The survival of the fittest will ensure that the strongest genes are passed on to subsequent generations.