Keith Broomfield

A passion for nature

The racy sex life of the dunnock

I have been watching a pair of dunnocks in the garden and it is easy to see why this is a bird that many people overlook. It does, after all, have rather unremarkable brown-streaked plumage and a tendency to feed out of sight beneath shrubs and bushes.

But appearances can be deceptive; for the dunnock has a most racy sex life which if replicated amongst the good folk of a country parish would be deemed as quite scandalous.

The dunnock indulges in virtually every mating strategy possible. More than one male can be paired with the same female, or a male can be paired with more than one female. And two or more males may be with two or more females at the same time. But there are also some puritan birds who adopt the seemingly boring practice of monogamy.

Confused? Well it is all a game of adapting to the circumstances and trying to successfully pass on one’s genes to the next generation – or as one naturalist so aptly described dunnock breeding behaviour, a case of ‘every man for himself’.

In the scenario of one female and two males, the hen dunnock plays a very clever strategy. She will mate with one male, but then when the other male comes along he will peck at her rear which causes her to eject the sperm from the first suitor, before he too then mates with her. What all this means is that the two males think they are the fathers and will both therefore help to feed the young in the nest, dramatically increasing the chances of the brood being successfully raised.

If all this is not enough, at the peak of the courting season dunnocks may mate with each other up to 100 times a day. Furthermore, all this is happening right beneath your neatly trimmed berberis and cotoneaster bushes. Ooh-er missus, time for a lie down, me thinks.

This fascinating behaviour was only discovered in the 1990s and highlights how much we still have to learn about nature, even right on our own doorstep. Perhaps it also shows how we tend to take our more familiar creatures very much for granted and often pay them only cursory attention.

The dunnock illustrates this in other ways. Okay, so the bird does appear a bit drab at first glance. But look closer and the plumage is in fact rather intricate; a rufous brown with dark streaks and a lovely slate-grey head, throat and breast. It also has a most wonderful short and musical song at this time of year. One of my earliest memories as a child was finding a dunnock’s nest lodged in a moss-covered tree stump, the four eggs glistening like azure pebbles.

The most interesting life of the apparently unassuming dunnock should really serve as encouragement to us all to look that little bit closer at our everyday fauna and flora. In other words, the deeper you delve, the greater the surprises revealed. Sometimes quite shocking ones!

Our sleeping world

Tidying up the garden in preparation for winter, I came across three hibernating garden snails hidden beneath an ornamental rock. Huddled together, I was immediately struck by the attractive and intricate patterns inscribed upon their spiral shells.

One of the snails became dislodged from the underside of the stone, and as I turned it over I could see that the opening at the bottom of the shell had been totally closed off with a crust of hardened mucous so as to seal the animal safely inside and prevent it drying out. The heartbeat rate drops dramatically too so as to save vital energy. In effect, this trio of snails were as close to death as one can get without actually tipping over the edge.

The different strategies our invertebrates adopt to see them through the winter is an endless source of fascination for me. Beneath the soil, or in cracks and crevices in walls, or within a rotting tree stump, there is a whole multitude of life lying unseen. Many of these creatures don’t even exist in the adult form at all, but instead see through the winter months as eggs or larvae waiting to burst into life the following spring.

For the wasp, only the pregnant queens remain, holed up in some crevice in a wall or perhaps the attic of a house, waiting for the warmer weather and the chance to start up a new colony. Some adult butterflies too may be hibernating such as small tortoiseshells and peacocks and it is not unusual to find an individual in the corner of a garden shed or even in a bedroom cupboard. On warm days in March they will be among the first insects to emerge.

Other invertebrates, however, don’t need to hibernate and can often be seen during damp and mild spells. The clouds of winter gnats dancing over the garden lawn are always a sight that cheers the heart. And while garden snails go for the hibernation option, it is not unusual to see slugs out and about on a mild winter’s evening.

It seems rather perplexing why some types of slugs venture out in winter, whilst the related garden snail prefers to hibernate. Although it does appear that the garden snail is generally not very tolerant of the cold and in Scotland tends to be only found in the milder, coastal areas.

What is for certain is that both slugs and snails are important winter food our birds. It would be a veritable feast for a song thrush if one were to happen upon the three slumbering snails beneath my garden rock. Although many Scottish song thrushes head further south to spend the winter, there are usually a few that stay behind.

I like song thrushes, but these snails were appealing in their own way too, so I carefully placed the rock back again in its original position, making sure in particular that the animal I had accidentally dislodged was firmly out of sight from any predatory eyes.

Mauve Stinger

Why are there so many jellyfish in the Mediterranean this year?

I’ve been lucky enough to twice visit the Spanish island of Mallorca this year to engage in my passion for snorkelling.

The Mediterranean is such a diverse place for marine life and on almost every dive I come back having seen something new.

One feature this year has been the sheer abundance of jellyfish – most notably mauve stingers and compass jellyfish. But there were also comb jellies and ‘by-the-wind sailors’, the most unusual creature I think I have ever seen.

These jellyfish were especially numerous in the spring, but were still pretty prolific on my most recent visit in October.

In previous years when snorkelling in the Mediterranean I have only occasionally seen jellyfish – so what is going on?

It is an issue that is causing a bit of debate among marine scientists, with climate change, ocean acidification and pollution, and overfishing of predator species all being cited as possible reasons.

The mauve stinger (pictured) in particular is a most beautiful species, but let me tell you this; the sting is pretty nasty as I found to my cost in the spring. The Mediterranean is highly dependent on tourism, so it would be highly undesirable economically if this jellyfish abundance were to continue in future years.

Perhaps there is some unexplained natural phenomena going on – nature does tend to have boom and bust tendencies – and numbers will fall back in the future. But whatever the case, both scientists and tourism bosses will be monitoring the situation closely.

Wood pigeon

Why the humble woodpigeon is one of our most successful birds

I was out walking the dog through a stretch of thick pine plantation in Glen Devon when I stumbled upon the half eggshell from a woodpigeon lying by the path’s edge.

Once the eggs hatch in the nest, the mother woodpigeon will deposit the empty white eggshells some distance away. The remarkable thing about my discovery is that it happened right in the middle of autumn – and this in itself gives an insight into why the woodpigeon is such a successful and ubiquitous bird.

Virtually all our bird species breed in a relatively narrow timeframe in spring and early summer, but the woodpigeon is content to cast aside such hindrances and there have been records of breeding in Scotland in most months of the year. I imagine one reason they are able to extend their nesting season is by taking advantage of spilt grain in our fields after harvesting.

Even as I write this piece I can hear a male woodpigeon ardently cooing in the wood behind my house, keen to attract a mate. If he succeeds, then it could be early November before the young have fledged and are on the wing.

The pigeon family certainly does seem to have an inherent ability to adapt. Feral pigeons are, of course, common in our cities, but perhaps the most astonishing story lies in the expansion of the collared dove.

In what has been described as one of the most remarkable ornithological events of the 20th century, the collared dove didn’t even occur here until the mid-1950s when it then rapidly colonised the British Isles after spreading north-west from Turkey.

But it is not all plain sailing in the pigeon world, as highlighted by the passenger pigeon. A native of North America it made the tragic journey from being one of the most abundant birds in the world during the 19th century to extinction early in the 20th century. A lesson for us all.

River Devon

Autumn life on the River Devon

Down by the River Devon the first of the autumn leaves have started to swirl in the air whenever the wind blows, alighting gently onto the water’s surface before being carried downstream.

I like the autumn; the chilling of the air and the turning of the leaves. The Ochils too will soon change hue from tired shades of green to a blaze of ochre that has been fired up by the wilting grass and bracken.

It is a season that brings so much and out on the river dippers are uttering short bursts of soft song as they mark out their territories. Dippers thrive on the Devon and one only has to turn over a small stone plucked from the shallows to find the reason why. The underside of such pebbles will invariably be crawling with small insect larvae – an abundant source of protein for the dippers to feast upon.

I disturb a heron as I make my way along the bank. Herons often have favourite fishing stations and those on the Devon particularly like to position themselves at the top of shallow rapids. Trout are on the move to spawning areas at this time of year and present an easy target for the herons as they ascend these shallow, bubbling stretches of water.

Trout have other enemies here too. Only recently I came upon an inquisitive mink that eyeballed me from in among tangled tree roots on the bankside. It soon tired of this staring game and plopped into the water and disappeared from view. Mink are the most accomplished swimmers and trout are one of their principal prey items.

Although the mink is an undesirable alien species to these parts, there is no denying that they are rather attractive creatures in their own right, thick furred and lithesome. One must never forget that it is not their fault that they are here, and as such, deserve at least a modicum of our respect.

Haunting calls of tawny owls fill our night air

Over the next few months as the nights get perceptibly longer, our tawny owls will in turn become increasingly vocal as young birds try to make their mark and form territories. The owls hoot and screech from just after sunset right through to dawn, making it one of the busiest times of year in the owl calendar.

Setting up territory is an energy sapping business, but it is also one of the most important things a young owl has to do, if it is to thrive and successfully breed. Tawny owls generally mate for life, and once a pair has established a territory they will defend it doggedly throughout the year from other owls.

A good territory that offers safe nest sites and fruitful hunting areas for voles and mice is like gold-dust, and incumbent owls do not take too kindly to young pretenders trying to move in. The young owls, therefore, have to tread carefully as they continually call so as to determine areas that are vacant.

It is a haunting experience to be out in the woods just after dusk and listen to these tawny owls engage in their vocal duels. The quavering “hu…hu-hoooo” is the main call of the male, while the female’s principal vocalisation is the more strident “kee-wick” call, which the Scottish naturalist David Stephen likened to an Indian war whoop.

Gilbert White, the pioneering 18th century nature diarist, was also greatly intrigued by the subtle variations in the call of the tawny owl. He wrote: “My musical friend, at whose house I am now visiting, has tried all the owls that are his near neighbours with a pitch-pipe set at concert pitch, and finds that they all hoot in B flat”.

However, he recounted later of instances of other owls hooting in different keys. White wondered: “Do these different notes proceed from different species, or only from various individuals?”

It is such inquisitive questioning that has led to our much more comprehensive understanding of the natural world today.

Aspen

The trembling aspens of Strathdevon

Most mornings I trek up a small hill overlooking Strathdevon and one of the joys of the walk is a small group of aspen trees growing by the side of the path.

At first glance these trees appear rather unremarkable, but looks can be deceptive, for when the wind blows something quite remarkable happens; the leaves begin to tremble and quiver in delightful fashion. Indeed, the Latin name, Populas tremula, means ‘trembling poplar’ and to sit by one and listen to the wind rustling through the leaves is really quite addictive.

The early 20th century poet Edward Thomas eloquently wrote of how the ‘the whisper of the aspens’ could not even be subdued by the ‘ringing of hammer’ and the ‘clink and ‘hum’ emanating from a local blacksmith.

Folklore states that this trembling of the leaves was an indication of some secret guilt – most likely because it was believed to be the wood used to make the cross on which Christ was crucified. One book I came across on Celtic traditions said the ‘aspen tree was particularly loathed’ because it ‘had haughtily held up its head while all the others in the forest had bowed down, proud that it had been chosen by the enemies of Christ as the wood for the cross’.

The leaf stalks of the aspen are quite long and flattened; a combination that makes the leaves flutter so easily in the breeze. I like these Strathdevon aspens for other reasons too, and the chances are that at least one of them will hold foraging blue or great tits whenever I pass.

Like the birch or the rowan, the aspen is very much a pioneering tree that is among the first to colonise new areas of open ground, often where the soil is poor such as in hilly areas.

This means they are important ecologically because they help to enrich the land through their shed leaves, thus preparing the way for other types of tree such as oak that are much fussier in their requirements.

Rowan

The importance of the pioneering rowan

At the head of one of the narrow glens dissecting the Ochil Hills there is a fine rowan tree I know that maintains a tenacious foothold in a rocky fissure.

Nothing unusual in that you might say, but a couple of years ago a mistle thrush built a nest in its upper crown and successfully raised a brood of chicks. In other words, if it wasn’t for the rowan, there would have been no breeding mistle thrushes in this part of the glen. This single and unassuming tree had played a small but nevertheless important role in enhancing the overall biodiversity of the area.

This is why I always look upon the rowan with much affection. They are pioneering trees gaining tenure in hilly areas where few other trees are ever found. Often known as the mountain ash, it is undoubtedly one of our most attractive trees, especially at this time of year with their branches festooned with heavy hanging bunches of scarlet berries. But the show isn’t over yet and as autumn really begins to take hold the leaves develop a stunning reddish hue. In Gaelic the rowan is rather appropriately known as rudha-an – ‘the red one’.

As well as being a handy place for birds to nest, the rowan supports wildlife in many other ways too. Winter thrushes such as redwings and fieldfares just love to feast upon their berries, and in spring the rowan is adorned with vibrant creamy white flowerheads that are magnet for bees and other insects.

It is hardly surprising therefore that the rowan is so closely engrained into our folklore. It has been associated with witchcraft since the earliest of times and Celtic Druids venerated it for its healing and medicinal properties. The tree was often planted in churchyards and near houses to ward off witches, and even up to the early years of the 20th century rowan boughs were hung over farm buildings in the Highlands. In some parts of Scotland cutting down a rowan tree is still considered a harbinger of bad luck, especially when close to a house.

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