Nature Notes - 2018 archive

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By Martyn Stenning

December 2018

I am in France again monitoring the autumn movements of birds in Aquitaine. We have seen chevrons of hundreds of European common cranes flying over and calling to each other as they go with little mechanical ‘purrs’. We have also had a grey heron in our garden, I think it was hunting the moles that punctuate the lawn with their hills of graded soil. This morning we saw a flock of about 40 northern lapwings landing in a ploughed field. These elegant waders often feed together on worms and other invertebrates and seeds, unusually for birds, they like to feed at night by moonlight.

There are currently large flocks of common chaffinches here forming winter foraging flocks, searching out seeds in the arable fields, especially those fields that were used to grow sunflowers. Chaffinches go into eclipse during the winter, which means that their colourful feathers are obscured by brown extensions rendering them cryptic in the brown winter fields. However, these brown feather tips get sloughed off in the spring revealing the pink breast and slate blue head.

We have a resident pair of cirl buntings living in the garden all year round. In France these are called bruant zizi because the male cirl bunting sits at the top of a tree calling zizi – zizi – zizi all day. Bruant simply means bunting. Cirl buntings are rare in Britain.

We have also seen flocks of cattle egrets in the fields nearby. These birds are usually associated with zebras and wildebeest in Africa, but are becoming increasingly common in Europe, including occasionally in Britain. Cattle egrets are similar to the little egrets that we now often see in coastal Britain which started colonising southern England about 30 years ago. Little egrets have black beaks and yellow feet and are usually solitary, but cattle egrets have yellow beaks and black feet and are usually seen in groups. Both are a type of white heron but are smaller than our common grey heron.

We have also seen many very large flocks of woodpigeons flying over as they head south for the winter. These are seen as fair game by the hunters of France who are referred to as Palombiers or pigeon hunters.


November 2018

I thought today I would write about my favourite bird – the blue tit. What are they doing now? Well, they would all have finished moulting by now and have a full set of beautiful new feathers. Winter is the best time to watch birds as there are fewer leaves on the trees and the bird’s plumage is at its best. In Britain, where we have our own sub-species called Cyanistes caeruleus obscurus, the females and surviving male juveniles will be on the move. Most of them move about 60 kilometres (37 miles) in a south westerly direction, while the adult males will remain on territory guarding it and the cavity they have chosen to display to a prospective mate in the spring.

The blue tits that move away for the winter will team up with other small birds such as long-tailed tits, great tits, marsh tits, goldcrests and chiffchaffs to form a mixed species foraging flock. These flocks will rampage through the countryside and gardens searching for food and watching out for predators. Many eyes will ensure that any sparrowhawk or other hunter nearby will be spotted. Also, they communicate constantly with each other with many calls including what is called the hawk alarm. This is a high pitched elongated seeee tone which they will all understand means that a hawk or other avian predator is nearby. They will also be telling each other about any food that they find. However, if they stray into a resident male blue tit’s territory, they can expect to be confronted with a tirade of blue tit anger calls and a display of strength and fury.

This will be the status quo until the winter solstice on or about 21st December when things will begin to change. The adult male blue tits will then start to regularly sing and show off to any passing eligible females that venture into his territory. He will occasionally perform the ‘moth flight’ which entails slowly flying down to the nest hole from a high perch while calling and quivering his wings. He will then enter the cavity and pop out again to show the female that he has sole right to it, and it could be hers to build her nest in and lay her eggs during the coming April. Many females will ignore him as they will prefer to move back to the area that they bred in last year, but one will decide he and the cavity are ok and stay with him for as long as it takes to breed.


October 2018

The days are getting shorter as the equinox approaches on about 21st September when the day time will equal night time the world over. Then, the northern hemisphere days will be shorter than the nights and the southern hemisphere will experience the opposite, until the spring equinox next year on or about 21st March.

These landmarks in time will be recognised and reacted to by organisms the world over. Deciduous trees start losing their leaves, summer visiting birds will leave Britain and winter visiting birds arrive. Britain probably hosts more wintering bird species than summer ones.

There are many species that use British coasts as a winter larder, birds such as curlew, grey plover, golden plover, knot, dunlin, sanderling, redshank, greenshank, ruff. Meanwhile, in the woods and fields redwings and fieldfares arrive along with wintering chaffinches, bramblings, blackbirds and song thrushes, the latter four, largely from Scandinavia, augment our resident populations. Many of these birds will have been moulting after about the summer solstice which is the longest summer day on or about 21st June. Moulting usually takes several weeks and results in a strong bright plumage ready for tough autumn and winter weather and migration flights. Some birds, such as the waders mentioned above, have a winter plumage that is a different colour compared with their summer plumage. Most waders become grey during winter and flock together on muddy foreshores to hunt marine invertebrates such as shellfish, crustaceans and lugworms.

There are flowers that bloom in the autumn also such as the tiny white spiral flower stems of autumn ladies tresses, which is a type of orchid, and the purple or white flowering wild cyclamen whose flowers appear before the leaves do. Ivy too flowers in the autumn and provides some late nectar and pollen for honeybees, butterflies and bumblebees.

As the nights get colder, some animals prepare to go to sleep for the winter such as all the reptiles; snakes, lizards and tortoises also amphibians; frogs toads and newts and some insects such as tortoiseshell and peacock butterflies.


September 2018

What a hot summer we have had! The beast from the east is now a distant memory when we had prolonged freezing temperatures from about 26th February to 3rd March. The one thing that we can predict about climate change is that the weather will become less predictable and more extreme over indeterminate periods.

Nature reacts to these events in different ways. Many migrant birds such as swifts and house martins were late arriving on their breeding grounds this year. Many species were down in number. However, there will always be some individuals that will be well adapted to the prevailing conditions and will breed successfully.

The unusually warm seas have generated population explosions of jellyfish. The warm land has resulted in a die-back of mosses. This will be welcomed by gardeners who like grassy lawns as the grass is more resilient to drought and will green-up again once the rain comes.

Amphibians such as frogs, toads and newts have probably suffered badly, first from being frozen during February and March and then from desiccation during June, July and August. Fish too will have problems in small water-bodies such as ponds and small streams. However, there will always be other organisms that will consume these.

In nature, the idea of disaster does not really exist, just changes in conditions. What is bad for one group of organisms is usually beneficial to others. Many readers will remember the ‘hurricane’ of 16th October 1987 when about 17 million trees were blown down during the early hours of the morning. Many people called this a disaster. However, in the wild-wood, trees came down, but most did not die unless people went in and cut them up and removed them. Most trees remained alive and just grew from horizontal stems. Those that did die provided food for billions of fungi and the beetles that fed off the rotting wood. These went on to feed increasing numbers of woodpeckers and other animals which also increased in numbers. Meanwhile, the clearings created by the fallen trees caused an abundance of woodland plants such as bluebells.


August 2018

I shall focus on swifts today.  These small almost black birds of the air should be familiar to all of us because they scream as they fly through and above the buildings of Uckfield and other European towns.  They often breed in the roof of Holy Cross church and other tall buildings.

Swifts can live for more than 20 years, most of which is spent flying.  Swifts are fast flyers and hold the record for maintained flight, often not landing at all for more than 10 months!  They feed, drink, sleep and mate all while flying.  When they want to sleep at night, they fly up to over 1000 metres above sea level and drift in the semi darkness sleeping as they fly, sleeping for short periods at a time.  Then, when dawn breaks, they descend to the insect zone, where they snap up all the insects they encounter as they fly.  Swifts are 100% dependant on insects and other invertebrates such as ballooning spiders for food. 

The latter statement deserves explanation; ballooning spiders are small spiders which make gliders from the gossamer threads they use for webs.  They then launch themselves into the wind and travel vast distances, but some are also snapped up by swifts and other birds.

Swifts arrive in Europe from the end of April to mid-May, find their nesting cavity, usually in a building and lay 2 or 3 white eggs in just one brood per year.  Each egg requires about 19 days of incubation, this duty is shared by the male and female.  Both parents collect invertebrates on the wing for their youngsters that take about 6 weeks to grow and mature before they are able to take their maiden flight, and are then independent, finding their own food on the wing as they fly with their parents in screaming flocks around the towns that they inhabit.  They also fly off into the countryside searching out good places to catch flying insects and spiders.  Most swifts will have left Europe by the end of August.  They are among the last migrants to arrive on their breeding grounds and the first to leave.

Swifts spend the winter south of the Sahara Desert, flying around Africa finding food and water on the wing as they move to almost anywhere that insects can be found.


July 2018

Writing this in June, as we rapidly approach the Summer Solstice (longest day), I am experiencing the huge build-up of biomass that results from the increased input of energy from the sun as the days get longer.  It follows that the more energy there is entering the northern hemisphere, the more life is regenerated, first from photosynthesis by green organisms such as plants and algae, and then from the animals that feed on these.  For example, the circa 250,000 leaves of a deciduous oak tree can in some years be completely defoliated by hundreds of moth caterpillars, each one eating up to 10 leaves before pupating.  However, one blue tit can eat from 70 to 100 caterpillars each day, and there can be as many as 18 young blue tits in one nest, plus 2 parents.  That is about 2,000 caterpillars eaten by that one family in one day.  There can be as many as 4 blue tit families in one hectare of woodland, so it is possible that up to 8,000 caterpillars could be consumed every day for the 18 to 20 days between hatching and fledging (leaving the nest), that is about 160,000 caterpillars consumed at some time between the spring equinox and the summer solstice sustaining up to 80 blue tits per hectare.  And this is not all, sparrowhawks time their breeding season to coincide with the fledging of blue tits which they feed to their young.  One family of 6 sparrowhawks could consume as many as 40 blue tits in one day!  When all this is over, the oak trees produce a second flush of leaves by 1st August, this is called Lammas growth, because it coincides with the ancient feast of Lammas or Loaf Mass.

Have you ever been involved in hay-making?  This is when a farmer will cut the grass that has grown and is ripe for cutting in June.  The grass has absorbed all the energy from the sun up to the solstice and produced a huge bulk of grass tissue, tasty and energy giving for the cattle and horses that eat it.  As many as 8.4 tons of hay can be harvested from one hectare of a good grassy field.  If one cow can eat 24 kilograms of hay in a day, this would sustain that cow for about 42 days.  That cow can then sustain quite a few people in the form of milk or beef.  In ecological terms, this dynamic system is known as ecosystem services, none of us could survive without them.


June 2018

Late snow, early heat, this is what I call climate change!  This year the temperature has been up and down like a yoyo.  I have a flippant theory that Britain does not have a climate, just weather.  However, one thing does not change from year to year, and that is the gradual increase of day-length from the winter equinox (c. December 21st) to that of the summer c. June 21st).  We are rapidly heading for the latter.  Sitting outside in the evening during the early May bank holiday weekend was great.  However, the temperature has now dropped again.  This seesawing of temperatures must be playing havoc with the insects as I am seeing very few here in Uckfield.  This is going to be a problem for the insectivorous birds and bats who depend on large numbers of insects for survival.  One striking absence is house martins, I have not seen one in Britain yet this year.  These little anthropophilic birds feed on large amounts of insects, nest in the eaves of our houses and produce 2 or 3 broods per year usually.  They winter in Africa and then follow the gradual appearance of insects as the wave of emergence proceeds north with the increasing day-length.  The flight north from central Africa to Britain can take as long as 3 months.  However, if the insects do not emerge, the birds will not move and may not be able to breed.
There has been much in the news recently about neonicotinoids, these are chemical insecticides that modern farmers are using to eliminate insects that affect crop productivity.  These chemicals are systemic (are taken up by the plants) and persistent (they do not decay quickly).  As field sizes get larger and more land is cultivated, the spread of these insecticides has been increasing, and they are not selective, they will kill all insects and probably other invertebrates as well.  This includes the bees that pollinate our fruit crops.  However, the EU voted to ban the use of these insecticides by the end of 2018 with the exemption of greenhouses.  Also, these chemicals are on pet flee treatments, in stables and animal transport vehicles, which account for about a third of all their uses.  These uses are set to continue.  We can only hope that alternatives can be found before all our insects and the other animals and plants that depend on them, disappear completely.


May 2018

“O, to be in England now that April is there”.  Thus, pined Robert Browning when abroad.  I have written about this poem before, but I was in England then.  I am now in France and face an explosion of nature earlier and more abundant than usually experienced in England.  That is why I am here, to study how the biodiversity of our planet increases closer to the equator.  I never experienced visiting a foreign country as a child, but some of my friends did, and my first question on their return was: “what wildlife did you see that we do not see in England?”.  The reply was a mind boggling list of birds like hoopoes, rollers, storks and cranes.  Also, butterflies such as swallowtails and  large green lizards.  I have seen all these now and much more.  Please do not misunderstand me, I love the biodiversity of England and know it very well.  It is just my wish to understand global ecology that drives me to travel.  Just like learning a language, it is hard to be fully competent unless you actually spend time in the country in question.
Cuckoos, swallows and blackcaps arrived here in France in late March/early April.  Probably a few days earlier than in England.  Also, birds such as the golden oriole and the zitting cisticola, the latter was previously called the streaked fan-tailed warbler before being renamed recently.  Lizards and butterflies (including swallowtail) have been visible for several weeks, orange tip butterflies are particularly numerous as they search out abundant lady’s smock, also known as cuckoo flower and milkmaids, to lay their eggs on. Brimstone butterflies also abound searching for buckthorn and alder buckthorn for the same reason.  Insects not often found in England occur, such as carpenter bees and praying mantises, also, some less welcome such as aggressive Asian hornets whose stings can be lethal.  Walking through the woods and fields of France reveals sights not often seen in England such as abundant lungwort, grape hyacinth and very early purple orchids.  I visited the coast last week, and, when the tide was out, besides finding wild oysters, I also saw a species that I had never seen before.  It looked like a coral but turned out to be a honeycomb worm colony.  This animal forms colonies that create reefs, mostly in Mediterranean climates, but does occur on some British coasts.


April 2018

The cold snap of late February and Early March this year has held up the end of winter like a coiled spring.  All of a sudden, the daffodils and crocuses are blooming and the early spring herbs are shooting out of the ground like little green rockets.  Insects also such as bumblebees, flies, butterflies and mosquitos are emerging.  Molehills are springing up like little mountain ranges in the lawns.  Worm casts are also being deployed like the piping of icing on a grassy cake.
Spring can feel like a very personal process of recovery after surviving a chilly dark winter.  I am sure it feels the same for other organisms as they celebrate the return of the good weather with their blooms, bounds and beautiful birdsong.  Conspicuous at this time is the song of male great tits calling ‘tee-cher tee-cher tee-cher’.  This has been called the melt-song as it usually coincides with the melting of snow.  In science writing, this change of the seasons is called phenology.
Everything in nature has its time and place.  The study of the places where organisms live is called ecology.  This word is derived from the Greek words oikos logos meaning home study. In the science of ecology, we study how organisms relate to their home environment.  Many of these organisms provide us with essential environmental services, such as bees and other animals pollinating flowers so that the flowers can produce fruit containing viable seeds. Beavers build dams in which they sleep and breed and which also create pools where the water-plants such as water cress and angelica can grow providing food for the beavers and also us humans if we care to collect it.  The water that the dams retain can ameliorate flooding further downstream, helping to prevent the misery of our buildings being flooded.
All green plants and algae have chlorophyll in their bodies that generates the oxygen that we breathe.  The trillions of bacteria, fungi and other organisms break down dead material generating fertile soil in which new plants grow.  The list of the ways in which nature serves our lives is almost endless.  We should never forget that and be careful to teach our children how dependant we are on the services that come from the natural world.


March 2018

I am writing this in Aquitaine, about 500 miles (750 km) south of Sussex.  The weather tends to be a little milder here with temperatures about 5 – 10 degrees higher generally and less rainfall.  Consequently, the signs of spring tend to appear a little earlier.  Yesterday, we saw our first flock of about 50 common cranes, first rising on a thermal gliding round and round to gain altitude, and then after about 20 minutes they formed a chevron in the sky and flew off to the north-east towards their breeding grounds in north eastern Europe.  A few also breed in East Anglia.  We were also able to photograph a white stork perched on the top of a telegraph pole, newly arrived from Africa, and can be watched breeding here in Aquitaine.  Almond blossom is also beginning to appear and other birds such as the robin, mistle thrush and blackbird are paired up and preparing for reproduction.  Indeed, I suspect that the mistle thrush has already got a nest with eggs, as these are regular early breeders often nesting as early as February, even in England.  I have also been watching a magpie build its nest which, characteristically, also has a stick canopy over the nest-cup, in a tall tree nearby.
The first birds to start breeding in the spring are the resident passerines or perching song birds such as the many types of thrushes which include robins, nightingales, stonechats and blackbirds as well as the familiar ‘spotty’ thrushes.  Some owls such as the barn owl also make an early start.  Then the woodland migrants, such as the flycatchers, redstarts and warblers, especially chiffchaffs, sing in chorus, pair up, build nests and lay eggs, so that they can feed their nestlings on the short-term seasonal abundance of emerging insects which in turn feed on the newly sprouting leaves in the deciduous trees.
As the season progresses from the spring equinox (21st March) to the summer solstice (21st June).  For single-brooded birds such as blue tits, this is the critical window of opportunity to produce a brood of fledged young. Multi-brooded species such as swallows and house martins, which feed on flying adult insects, keep churning out offspring until the autumn.  However, the seabirds, also single-brooded, do not actually start laying eggs until May or June.  They synchronize their breeding with the northbound migration of the shoals of herring.


February 2018

I saw my first flowering celandine during the last days of December! This is amazing as these little yellow star-like flowers do not usually appear before March.  I have also seen countless expanded hazel catkins during early January.  If you look closely at the hazel twigs, you can see the beautiful tiny deep red female hazel flower, which, if fertilized by the wind-blown pollen from the catkins, will become a delicious hazel nut later in the year.  The fact that hazel has the male and female flowers (organs) on the same plant means that they are monoecious or hermaphrodite, meaning also that they can fertilize themselves or other individual plants (trees) of the same species.  Other plants such as Holly, our only native broad-leaved evergreen tree, are dioecious, meaning that they have male and female plants.  Only the female holly plants (trees) bear berries, which of course contain the seeds that can go on to become new holly trees.  Many birds, such as members of the thrush family, love to eat holly berries, but the birds do not digest the seed within the berry. The seed passes through the digestive system of the bird and passes out with the faecal droppings, often at night while the bird is roosting. Consequently, it is often possible to see where birds roost by finding young holly or elder seedlings a long distance from the nearest parent tree.  This is known as a dispersal system that has evolved because it is a successful strategy for procreation and the colonisation of new areas.
Animals, on the other hand, have evolved their own methods of dispersal by using parts of their own bodies such as legs and wings to take them into new areas, and by doing so, often transport other organisms, not only plants but fungal spores, other animals such as lice and fleas, and also microbes such as bacteria and viruses.  The upshot is that living organisms are continuing to spread throughout the world, and some thrive where they end up but others die, because they find themselves in places that are too hot or cold, or too wet or dry, or too acidic or alkaline.  However, every organism that has been sexually reproduced is unique, this is due to gene mixing which generates variation.  We only have to look at the wide variety of dogs (wolves) living in our homes to see just how variable one species can become.


January 2018

The recent cold weather here in the maritime north Atlantic island of Great Britain has sent nature running for cover.  Like us, most other animals, plants, fungi and microbes prefer to take refuge in locations warmer than average for the time of year where they usually live. 

You may say that plants and fungi do not move, yes?  Well, actually, most plants are large enough to move bits of their life-support systems between warm and cold parts of their extensive bodies.  That is, during the summer, when the air temperature is above 10°C, most of the activity is above ground and the green bits grow large and bright, usually culminating in producing some kind of seeding fruit.  However, during the winter, these plants recede into the ground where, just about 10 centimetres down, the soil remains at about 10°C . The roots continue to grow, and some plants produce tubers, others corms which are really subterranean stem tissue; others produce bulbs, which are really compressed white leaf material.  During winter, the tissue above ground either goes dormant or dies off completely, leaving a powerful refugium below ground.  We often like to eat those in the form of carrots (root), potatoes (tubers), Chinese water chestnut (corm) and onion (bulb).  Even the seeds are usually hiding in leaf litter or below ground, and we eat those in the form of rice, beans and bread.
Fungi are also below ground, indeed the largest living organisms on the planet are probably fungi which include individuals spreading out underground for sometimes several hectares.  Fungi only come above ground to produce tiny airborne spores from their mushroom fruiting bodies, which drift on the wind into new habitats to make new fungi.

Animals, on the other hand, have the ability to fly into refugia such as caves (bats) or dig into the ground (tortoises), crawl under tree bark (earwigs) or swim to the bottom of ponds (frogs).  Many birds (e.g. cuckoos) and butterflies (painted ladies) fly to warmer countries, others move to warmer habitats (blue tits to gardens and reed-beds, peacock butterflies to garden sheds and tree stumps).  We humans too prefer to stay indoors and keep warm.  However, when the sun shines and the temperature rises out we and they all come again and life continues.


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