When I mentioned that I was writing a book on the wren, many people (apart from naturalists) told me they had never seen one. While in some ways this is odd – after all, there are estimated to be at least eight million breeding pairs of wrens in Britain – in other ways it is quite understandable.

The wren lives its life in a very different way from most other birds – whizzing from place to place on those short, stubby wings, or hiding away in the undergrowth, searching for tiny insects on which to feed itself.

What do wrens look like?

Wrens are tiny, dumpy brown birds with long legs, a fine bill, short round wings and a short, narrow tail.

Where do wrens live?

Most garden birds, including other favourites such as the robin, blackbird and blue tit, are essentially woodland species, for which gardens provide an ideal replica habitat, with places to feed, roost and nest. Up to a point, the same is true of the wren, and indeed wrens do breed in woods and forests.

Yet elsewhere in Britain, unlike these other arboreal species, wrens can be found on heaths and moors, along coastal cliffs and headlands, and on remote, offshore islands. I have seen wrens in virtually every laInd habitat, apart from the high tops of mountains.

The reason for this catholic choice of dwelling places is that the wren lives its life on a very different scale to us, and indeed to most other songbirds.

As Max Nicholson, the giant of 20th-century ornithology, noted: “The wren cannot be adequately described as a bird of woodlands, gardens, fields, moors, marshes, cliffs or wastelands – although it is all of these – but must be looked at rather as a bird of crevices and crannies, of woodpiles and fallen trees, of hedge bottoms and banks, walls and boulders, wherever these may occur.”

More like this

In other words, the wren can live almost anywhere – hence its position as Britain’s most common and widespread bird. It also explains their rather puzzling scientific name, Troglodytes troglodytes, meaning cave dweller – which probably refers to this diminutive bird’s habit of exploring nooks and crannies in search of food.

What do wrens eat?

Wrens feed on tiny invertebrates, including spiders, flies, beetles and ants, which they grab with that long, pointed bill. Because these creatures are available all year round – unlike, for example, some flying insects – wrens have little or no need to migrate.

This is also where the wren’s small size comes into play. Few other species can survive on such tiny morsels of food, and few others have the ability to find their prey so effectively – searching constantly in hidden places, and moving from one place to the next in a blur of energy.

“A wren’s world… is more comparable in some ways to a mouse’s than to our own,” Nicholson asserted, and they do behave much more like a small mammal than a bird. That may be one reason why most people so rarely see them.

How big are wrens?

The other thing people tell me about the wren, often with great confidence, is that it is Britain’s smallest bird. However, the wren comfortably outweighs the true holder of that title, as I discovered when naturalist and bird ringer Ed Drewitt simultaneously trapped a wren and a goldcrest in my garden.

To our surprise, the wren was fully twice as heavy as the goldcrest, tipping the scales at 10g compared to the goldcrest’s 5g. But at the same weight as a new £1 coin, the wren is still very small, which makes it vulnerable to harsh winter weather, when food can be hard to find.

The wren's length is 6-10cm while its wingspan is 13 - 17cm

How do wrens survive winter

Desperate times call for desperate measures, which in the wren’s case means forsaking its usual solitary existence each evening, and ‘buddying up’ with its rivals to keep warm. Wren roosts are rarely seen, as they are usually behind dense vegetation, such as ivy. But from time to time, wrens take advantage of the nestboxes we provide for our garden birds. They can do so in incredible numbers – during the winter of 1969, one observer in Norfolk counted more than 60 wrens entering a single nestbox. But for such a normally solitary and pugnacious bird, this forced cohabitation does not come easily.

Wildlife cameraman Mark Payne-Gill recalls filming wrens roosting in a disused swallow’s nest in Essex, on a chilly winter’s afternoon. Having filmed several wrens entering the nest and settling down for the night, Mark was just about to pack away his camera when he heard a series of loud and increasingly angry sounds from within. A few moments later, one of the wrens flew out, rapidly followed by the others. They then proceeded to hold the avian equivalent of a talent show ‘sing-off’ – even though by now it was almost dark.

Mark watched enthralled as the birds then flew back into the nest, and the whole scenario played out again – noises, squabbling and a sudden eruption of wrens, followed by another bout of singing and displaying to one another. Only when darkness finally fell, did they stay put inside the nest, presumably realising that any further squabbling was not only fruitless, but potentially fatal.

What do wrens sound like?

Song is another important aspect of the wren’s feisty character. No other British bird, with the possible exception of Cetti’s warbler, has quite such a loud voice for its size. And even though many folk have never seen a wren, at least not knowingly, when I play them a recording of its song, they usually recognise it. Few bird songs are quite so distinctive, and quite so full of character, as that of the wren. Some bird books erroneously suggest that it ends with a loud trill. In fact, as nature writer Dominic Couzens memorably notes, the wren’s song has “a twiddle in the middle”.

When he sings, a male wren shakes his wings and moves from side to side on those spring-loaded legs, as if he can barely contain the sheer energy inside his tiny body. This is then released through an astonishing burst of sound – described by the 20th-century Irish writer, editor and essayist Robert Wilson Lynd as being “as brilliant as a rainbow in a wet sky – brilliant as a dance of rainbows”.

The man who knew the wren better than anyone, the Anglican priest and ornithologist Edward Allsworthy Armstrong, who died in 1978, was more prosaic in his analysis of the wren’s song, calling it “striking” and “cheerful”, but admitting that it is “somewhat unmusical”.

Armstrong, who began his long studies of the species when he observed a wren outside his study window during a World War II bombing raid, went on to analyse the wren’s song in forensic detail. He noted that it typically consists of five or six distinct phrases per minute, each containing what sounds like between 30 and 50 separate notes. Later ornithologists, using more sophisticated recording equipment, have revealed that each phrase sung by the wren may in fact contain up to 130 notes.

So, a typical wren sings between 500 and 600 notes every minute, or at least 30,000 notes every hour. If we assume that a wren sings for three or four hours a day (and many do so for far longer), that is roughly 100,000 notes in 24 hours. Given that a wren may sing for four months or more, his annual output must be close to 12 million notes. No wonder, perhaps, that, unlike other songbirds such as the blue tit or robin, he takes very little part in raising his family.

Wren nesting habits

What he does do, at the very start of the breeding season, is build up to half-a-dozen ‘cock’s nests’, which he then proudly shows off to his mate, much in the manner of an estate agent showing a client around a property. Not that the female is all that impressed – indeed, she will usually reject the first few nests he shows her, before finally deciding which is in the safest place and closest to the best food supply, to give her the greatest chance of raising her brood.

Another rather unusual aspect of wren breeding behaviour is that the male builds a domed nest, so that his eggs and chicks are out of sight of curious predators. Apart from the long-tailed tit, dipper and house martin, no other small British songbird does this.

One theory is that because the wren’s ancestors evolved in the jungles of Central America (where many species of wren can still be found), they built domed nests as protection against snakes. Even though ‘our’ wren rarely faces that danger, it continues to follow the ways of its ancestors.

How many eggs do wrens lay?

Once the female has chosen the nest, she then furnishes it – bringing back hundreds of tiny feathers to make a soft, comfortable base on which she lays her clutch of five or six eggs.

Do male wrens have more than one mate?

She does all the incubating duties, but that does not mean the male can take a rest. Instead, he starts the process all over again, wooing a second female, and sometimes even a third. But in the far north of the wren’s range and on offshore islands, where food is scarce, wrens switch to being monogamous, giving them a better chance of raising at least one brood of chicks.

Are wrens known by any other names?

Not surprisingly for such a common and widespread bird, the wren has a multitude of folk names. These include ‘titty’ and ‘titty-wren’, along with variants such as ‘cutty-wren’, ‘chitty-‘wren’ and ‘tiddly-creeper’. There’s also ‘tomtit’ and ‘tom in the wall’ – in which ‘tom’ signifies something small, as in the children’s fairy tale Tom Thumb. ‘Two-fingers’ is another reference to its small size; and there’s ‘stumpy’, ‘stumpit’ and ‘stumpy-dick’, all of which refer to the wren’s most prominent feature – its sticking-up tail. But by far the most familiar to most of us is the nickname ‘Jenny wren’.

How may different species of wren are there in the UK?

Six subspecies of wren are known from Britain and Ireland. Five are resident endemics not found elsewhere, and one occurs here as a migrant. Shetland (zetlandicus), Fair Isle (fridariensis), the Outer Hebrides (hebridensis) and St Kilda (hirtensis) have their own ‘island’ subspecies, while Ireland, Wales, mainland Scotland and most of England have the ‘British’ wren (indigenus).

In the south-east of England indigenus intergrades with troglodytes, the subspecies found across the rest of Europe. That such a widespread bird should have so many subspecies within our region underlines the sedentary habits of our island forms, which also differ in size, colour and vocalisations.

The differentiation of these island races must have been rapid, because their islands would have been uninhabitable during the last Ice Age. Recent research has revealed that mainland wrens are adapted to local climatic conditions, with the larger-bodied individuals found in the north better able to survive extended periods of cold winter weather than their southern counterparts, something else that may have helped these subspecies to form.

(Mike Toms)

What's the secret behind the wren's success?

Armstrong suggested that the wren’s adaptability – changing its lifestyle to suit its surroundings – was the key to its success. And of all Britain’s birds, the wren can surely claim to being the most successful. Not only is it by far the most common species, it is also the most widespread. The British Trust for Ornithology survey Bird Atlas 2007-11: The Breeding and Wintering Birds of Britain and Ireland revealed that the wren is present all year round in at least 97 per cent of the 3,862 10km squares in Britain and Ireland. Given that the wren is less obvious than some other species, and so may elude even the most diligent observer, it may be even more ubiquitous.

In 2013, the magazine British Birds published a paper estimating our breeding bird populations. For me, one number stood out: that the humble wren, a bird so often ignored and overlooked, accounted for no fewer than one in ten of all our breeding birds. For such a tiny and unassuming creature, that is quite some achievement.

Did you know? The wren in popular culture

The wren features in the writings of Chaucer and Shakespeare, William Blake and John Clare, and most famously, in Edward Lear’s comic verse:

Two owls and a hen,

four larks and a wren,

have all built their nests in my beard.

The wren also appeared on Britain’s smallest coin, the farthing, from 1937 to 1960 when it was finally withdrawn from circulation (there were four farthings in a pre-decimal coinage penny). But the most intriguing way that wrens feature in British and Irish culture is the old annual ritual of the ‘wren hunt’, in which groups of boys would pursue a wren around their village each Boxing Day, before capturing or killing it and demanding a reward.

Main image © Getty Images