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Britain’s commonest bird, the wren, is also one of our smallest, weighing in at under 10 grams.
Britain’s third-smallest bird, after the even tinier goldcrest and firecrest, is also, perhaps surprisingly, our commonest breeding species. With upwards of eight million pairs, it is comfortably ahead of its nearest rivals, the chaffinch and robin (six million pairs) and blackbird (five million pairs), and much commoner than far more familiar garden birds such as the starling or house sparrow.
So if wrens are so common, how come we hardly ever see one? Their lack of visibility is mainly down to their shy and skulking habits. Unlike other garden birds, wrens prefer to shun the limelight, rarely venturing out into the open. They are far more likely to be glimpsed as they root around at the base of a shrubbery, or potter about a rockery, in both cases on the lookout for tiny insects, which they can grab with that short but sharp and pointed bill. It takes skill to notice a wren, and patience to get more than a brief glimpse, but if you do put in the effort, it is definitely worth it, for the wren is one of our most attractive breeding birds.
Its main feature is definitely its distinctive shape. Wrens are short and plump, with a cocked tail, which it holds up at a 45-degree angle from its body, and with short legs and a really subtle but beautiful plumage. Shades of brown, buff and black combine to give an overall chocolate-brown appearance. In flight, it whirrs along as if powered by clockwork, its tiny wings simply a blur. That small size conceals a hefty build, though, as a wren may weigh as much as 10 grams (⅓ oz), about twice that of the slender goldcrest.
As with so many small and elusive birds, by far the best way to discover wrens is by listening for their sound. The male wren utters the most extraordinary song for a bird so small: a series of very loud notes and phrases, gathering speed and usually featuring a trill, once described as ‘like an opera singer giving her all at the end of the aria’. No other small bird sings quite so loudly! They also have a distinctive, metallic ‘ticking’ call.
Wrens sing mainly in spring, often from a prominent position such as a fence post or the top of a shrub. At this time of year, the male is also very busy, as he has to build as many as half-a-dozen different nests. Known as ‘cock’s nests’, these are carefully inspected by the female before she chooses the best one in which to lay her clutch of five or six tiny eggs. In this way, she tests out the male’s commitment to her, and also picks the nest least likely to be discovered by a passing predator.
Wrens are not only found in gardens. They have colonised a greater range of habitats than any other songbird, including woods, hedgerows, farmyards, moorland, coasts and, most amazingly for a bird with such limited powers of flight, offshore islands. The isolated populations on Scottish islands such as the Hebrides, Shetland, Fair Isle and, most notably, the remote archipelago of St Kilda, have all evolved sufficiently to be considered separate and distinct races of the species. Indeed, the St Kilda wren – darker, larger and even louder than its mainland cousin – has a good claim to be a separate species, which would make it by far Britain’s rarest bird.
The wren’s ability to colonise new places is a legacy of its distant past. In fact, the wren is the only originally North American species to have colonised most of Europe and Asia. Back in its ancestral home, it is known as the ‘winter wren’, to distinguish it from 70 other species, including the cactus, marsh, sedge and canyon wrens.
