The secret life of the wren
The wren thrives in many different habitats but its lifestyle is so unobtrusive that people often claim they’ve never seen Britain’s most common bird.
Dwelling in nooks and crannies from highlands to coastal cliffs, discover why the wren remains Britain’s most common – yet least observed – bird
W hen 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.
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 land 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.” 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. 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.
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.
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 Solitary survivor
During the winter of 1969, one observer in Norfolk counted more than 60 wrens entering a single nestbox.