Archive for category: News

Continuing with the theme of seasonal change in the natural world, Let’s talk Spring (Printemps in French)! Time for migration of some animals, emergence from hibernation of others, and the springing up of annual flowering plants and the opening of leaves on deciduous trees.

Incidentally, we humans are natural also and respond to seasonal change. Perhaps the first thing we experience, as the days lengthen, is the singing of birds and the emergence of plants, such as winter heliotrope, snowdrop, crocus and daffodil. Hazel catkins also expand during January and February releasing pollen to donate to the tiny red hazel female flowers which also appear. The sea trout migrate up the rivers such as the Ouse and Uck during these months while the flow is good, in order to spawn among the gravel in the head-waters. Elvers (baby eels) too will be heading for Britain in large numbers to grow in our ditches and streams. Overhead, migrating birds such as chiffchaffs and blackcaps normally arrive in March. Our resident birds start to prospect possible nesting places, and early breeders such as mistle thrushes, barn owls and blackbirds may even start nesting and laying eggs in February and March.

The first insects that you might see could be bumble bees which can start flying when the temperature is about 8°C. Most other insects require at least 10°C. Maybe the first butterfly to emerge is the beautiful yellow brimstone that lays its eggs on the underside of buckthorn leaves, or the orange tip butterfly which uses ladies smock (milkmaids) plants. Another sign of spring is the dancing of gnats in quiet. still, warmer evenings during February and March. If you are a gardener you may see more earthworms and slugs as the days and nights warm up. You may also see emerging bats flying around the house lights in the evenings trying to catch the early flying moths as both animals emerge from hibernation.

As days lengthen, herbs, shrubs and trees start to break bud. Nature has ordered a rigid succession of leaf emergence First it is ground flora such as arum, ramsons, wood anemone and bluebell leaves emerging. Then the shrubs such as hawthorn, and climbers like honeysuckle. Finally canopy trees such as oak, along with the insect eggs laid on twigs producing caterpillars to eat the oak leaves and feed the nestling birds.

“In the bleak mid-winter frosty wind made moan”. The poet Christina Rosetti (1830 – 1894) wrote these words accurately describing this challenging time of year. All life is challenged by winter, but most living forms have adaptations that allow them to survive the cold. Cold blooded (poikilothermic) animals hibernate meaning they put their lives on hold and go into torpor. Many mammals grow a thicker coat of hair/fur/wool. Many birds migrate from cold regions where food becomes scarce, and fly to warmer places where food is more abundant. The general idea is to adapt and survive.

Plants have also adapted to live in regions where their growth and reproduction is optimal. If you plant a tropical plant in your garden, it will probably die when the frosts come. Likewise, if you try planting bluebells in a tropical country, they will probably die of heat exhaustion.

Badgers have adapted their reproductive behaviour to fit in with the annual cycle of weather in Britain. They make their maternity nests in the late summer or early autumn when the weather is still quite mild. Badgers do not hibernate, but they feed up on earth worms, frogs and other small animals, nuts and fruit during the autumn time of plenty and their activity is reduced during the cold months. Badgers can mate at any time of the year, but the fertile embryos delay implantation in the womb until December, then after about 49 days of embryo development, the babies are usually born underground during mid-February, often from multiple fathers as they tend to be promiscuous all year round. Litters can be from 2 – 6 young. The babies emerge from the sett during the night after about 8 weeks (c. mid-April) of being fed on their mother’s milk below ground. By this time, cold weather is less likely and days are getting longer and food more abundant. The female may continue to suckle the cubs for several weeks beyond then, but they will be learning about finding food for themselves during these outings. This way, young badgers have all spring and summer to feed up, grow and mature.

Living in a seasonal habitat is always going to be challenging, but in the tropics, seasons are less well defined by daylength and temperature, they are more defined by the amount of rainfall they get.

There are just three types of animals on planet Earth if you classify them by eye function. 1. Those that have forward vision only, like us and most spiders, these animals are usually predators; 2. those that have side-of-head eyes, virtual all-round vision such as chickens and butterflies, these tend to be prey animals 3. those that have no eyes, like worms and cave fish, live in dark places and have lost or never found the power of vision.

Eyes may be the single most improbable and miraculous organs of the body, a window on the world. Even the Evolutionary Biologist Charles Darwin exclaimed that it was “absurd” to propose that the human eye evolved through spontaneous mutation and natural selection. Yet evolve they did because evolution itself is an elegant and miraculous process.

Actually, even worms have cells that detect and inform them as to whether they are in darkness or light. From simple light sensors like these, eyes developed and improved gradually over many generations.

Predators and prey alike probably have the best eyes on the planet as their existence depends on them. A golden eagle has phenomenal eyesight and can see tiny prey movements from hundreds of metres away. Similarly, deer and antelope who have all-round vision, and who often live in herds, will spot a predator immediately unless the latter is well camouflaged, hidden and still. Feeding and survival for these 2 groups has been a process of refinement and skill development over many generations. The same can be said of humans as athletes continue to break records every year at sports meetings. We no longer depend on the skills and agility of hunters in order to eat, but we still try to improve the capabilities of our bodies. Animals will be doing likewise. However, some animals, like us, have adopted a cultivation strategy for their food. They still need good eyes, but use them for management rather than hunting or evading being hunted. Among these are ants who ‘farm’ aphids and scale insects. Lions who live with herds of antelope, getting to know them and identifying individuals that would be easiest to catch.

Autumn is the time for spiders, hunters that set gossamer insect traps.

There is a bird, fairly common in Britain, namely, about 80,000 pairs, that anyone living near or in a town or in the countryside, can see easily, and frequently, during the months of May, June and July, but is impossibly rare during the remaining months. This bird weighs from 31 – 56 grams, has a wingspan of 42-48 cm and is dark brown to black or slate grey for the most part with a small light patch beneath its beak.

This bird almost exclusively eats insects, but will also take spiders that are ballooning on gossamer webs. All this while flying continuously.

This bird remains on the wing all its life for about 10 months of the year even roosting on the wing at altitudes between 1000 and 2000 metres, gliding and sleeping on and off until dawn. This bird can also mate and drink water on the wing. The only time this bird lands is to make a nest in a building, tree hole (such as an old woodpecker hole) or in a nest-box, or on a craggy cliff-face. This bird is most fond of church buildings.

Both males and females share nest duties and often preen each other (allopreening) while at the nest. Their clutch of eggs can be from 1-4 but are usually 2 or 3. The eggs are long, elliptical smooth and white, but not glossy. Incubation takes from 19 to 27 days. This is so variable, because, in the nest, the young of this bird can endure short periods of hibernation in and out of the egg and their little bodies become dormant. This is when the adults find it hard to find food during cold spells of inclement weather often flying far and wide to feed, abandoning their nestlings for days at a time. The nestlings are in the nest from 37–56 or sometimes more days during which the parents feed, clean and warm them.

When they are ready to fly, the fledglings leave the nest at about 08:00 h when their parents are absent, and they find their own food from that day on for the rest of their lives of up to 20 or more years during which they fly the same distance as if going to the moon and back up to 7 times. By the beginning of August, most of these birds have left Britain and flown to Zaire, Tanzania, Zimbabwe and Mozambique. This bird, known for its screaming, very fast flying flocks, is the common swift (Apus apus).

Having studied biological/ecological science for many decades, I feel a bit concerned about how some human activities effect the natural world.

When we express concerns about the environment that supports us, some with other preoccupying, often commercial, concerns, label us as “bunny huggers” or non-pragmatic ideologists. It is true that I did keep pet rabbits as a child and so did our children. However, there are a few provisos that need to be made clear. First, keeping rabbits or any other animal is an opportunity to understand their biology, and this led me into an advanced education in that science subject. Secondly, rabbits are not native to Britain, but were introduced here by the Normans in the 12th century for their meat and fur. Therefore, rabbits have not contributed to the maintenance of Britain’s primeval natural biodiversity and may even have harmed it. For example, Natural England, the Government’s advisory body on nature conservation, actually pays people to control rabbits on some of our National Nature Reserves (NNRs). This is because rabbits sometimes cause serious damage to the biodiversity of native species rich grasslands, such as those found on the downlands of Sussex.

Following on, it is the total natural biodiversity, from bacteria to blue whales that regulates population levels of almost every global living thing, within balanced limits. In the past, some humans have kidded themselves that removing certain organisms would make life easier. This naïve attitude to nature sometimes resulted in a knee-jerk reaction to kill “vermin” such as birds of prey and foxes. Other folk exploited animals such as beavers and little egrets to adorn themselves, such that they became extinct on these islands. As a result, our native ecosystems have become unbalanced, raising more problems for us to deal with.

Currently, the science of ecology is revealing solutions to these issues and other environmental problems such as climate change, disease transmission and the rapid decline of plants and animals that our parents knew and loved, such as marsh marigolds, nightingales and otters. Some of these species are now returning. One solution is the preservation of green and blue ecosystems such as the forests and oceans that provide the oxygen that we breathe. It is a solution that we can all contribute to.