Wren

Bird of the Month December 2022: Wren

You might think that the obvious choice for December’s bird of the month would be the robin, that staple of snowy Christmas card scenes. However, the wren has a much older association with this time of year. This diminutive bird is known as the ‘winter king’ in the Netherlands for its habit of singing throughout the winter. And on St Stephen’s Day (or Boxing Day), a number of places uphold a tradition called Wren Day or the Hunting of the Wren, which was probably once much more widespread. So, meet this tiny bird with the big personality.

Small but Mighty

Wrens are the third smallest birds in the UK, after the goldcrest and firecrest. They are a dumpy, brown bird with subtle barring and a short tail that they often cock upright in a very distinctive pose. What they lack in size, though, they more than make up for with their characters and extremely loud song. In fact, you will often hear them long before seeing them, with their instantly recognisable song exploding out of a wall, hedge or bit of scrub. Like many birds, the song does vary slightly geographically. Along with a big voice, they have big personalities. Despite their habit of skulking through vegetation, when they do emerge, they give every impression of being more than willing to pick a fight with all comers.

Wren
This cocked tail pose is characteristic of wrens

They are our commonest breeding birds with 11 million territories recorded in 2016. This is in large part down to the fact they are happy to live in just about every habitat available in the UK. Gardens, woods, farmland, moors, wetlands, coasts and heaths are all inhabited by wrens. They can also live at surprisingly high altitudes. Many a time in Scotland I’ve heard a burst of song from a lone rowan tree halfway up a mountain. Their wonderful scientific name, Troglodytes troglodytes refers to the fact they often forage in holes and crevices as a troglodyte is a cave-dweller. They have longish, thin beaks like most insectivorous birds, and their diets consist mainly of invertebrate larvae and small spiders. This does mean that extremely cold winters affect numbers as food is much harder to find, even under bark and moss.

Family Life

For the male wren, the breeding season is an extremely busy time, even by most other birds’ standards. Females prefer males who have made multiple ‘cock nests’ in the territory for her to pick from. As a result, males may build between 6 and 12 different nests. The female inspects each before choosing her favourite to carefully line with feathers and lay between five and eight eggs in. The male also often has more than one female on the go, so has to repeat this process for all of them. Most will have two or three females, with four the highest number recorded. They build their domed nests in a variety of spots including wall crevices, tree holes, bramble thickets and amongst boulders.

Wren juvenile
The yellow gape and shorter wings and tail show this is a juvenile

The eggs hatch after just over two weeks with young fledging another two weeks or so later. Once the young leave the nest, both parents will feed them. In late spring and early summer, it is entertaining to watch these hectic family parties as they disperse around a territory. Youngsters seem to wait grumpily about for over-worked parents. Wrens will often have a couple of broods over a breeding season, so at times it can seem like there are wrens everywhere if they are present.

Wren feeding
Wrens mostly eat invertebrates

Island Subspecies

Wrens on four Scottish island groups have evolved to become separate subspecies. St Kilda, the Outer Hebrides, Shetland (excluding Fair Isle) and Fair Isle all have their own subspecies. The changes aren’t as dramatic as those seen by Darwin amongst his famous Galápagos finches, which evolved from one ancestor species into multiple ones, filling different niches on the islands. But there are noticeable differences, with the island wren subspecies all being obviously larger than their mainland cousins with longer, thicker bills. The St Kilda wren is the largest of the quartet and also differs in colour, with stronger barring and a greyer, paler plumage. The Shetland and Fair Isle wrens, meanwhile, are darker than their mainland counterparts. The island birds’ songs are louder than on the mainland and it is thought that this is so they can be heard better from the boulder beaches they often nest within.

Shetland wren
This Shetland bird is darker and larger than its mainland counterparts

Mainland UK also has two different subspecies. One inhabits the north and west of the country, while the other has a more south-eastern bias, although there is an overlap. Research by the BTO has found that each wren population has adapted to its local climate. Those living in the coldest areas are larger and able to carry more body fat to keep warm. Because wrens are quite a sedentary species, evolution into local subspecies becomes much more likely. Whether they will ever develop into full species remains to be seen. Genetic research suggests that the different UK subspecies have evolved since the last ice age, which is fairly recently in evolutionary terms.  

Shetland wren
The island subspecies often nest among boulders

Wren Day

So, back to that association between the wren and St Stephen’s Day. Historically, variations of a festival now celebrated as Wren Day in Ireland and the Hunting of the Wren on the Isle of Man took place in parts of England and Wales as well. With its origins almost certainly in pre-Christian times, in the past, practitioners hunted a real wren. Nowadays, where the tradition survives, participants put a fake wren on a pole or in a cage. Groups of ‘wrenboys’ or strawmen then parade around the nearby villages singing traditional songs. In Wales, the event took place between the 6th and 12th of January.

Wren Day in Dingle
These wrenboys, or strawmen, are part of the annual celebrations in Dingle, Co. Kerry, Ireland. Picture by Sarah Insole

For such a tiny bird, the wren has a lot of stories and traditions attached to it, hence the widespread nature of the winter festivals. In Celtic tradition, the wren signified the old year. Therefore hunting it in order to bring about the new year made a certain sort of sense. Many cultures also call the wren the king of the birds. In a traditional story that folk tale collectors including Aesop recorded, the birds hold a competition to see who can fly highest and thus become king of the birds. The clever wren hitches a ride with an eagle then, when the eagle gets tired, the wren carries on to win. The bird is regarded as clever or a trickster in many places as a result of the story. Some of the Wren Day songs refer to the wren as king of the birds too.

Wren Day Dingle
Straw costumes being made for Dingle’s Wren Day. Picture by Sarah Insole

In the UK, the wren appeared on the old farthing coin between 1937 and its last minting in 1956. This was presumably because many people thought it was the smallest bird and the farthing was one of the smallest denomination coins.

Farthing wren
The wren appeared on the old farthing coin between 1937 and 1956

The Winter King

It may be small, brown and dumpy, but the wren packs a punch well above its weight. Bold, loud and charismatic, it justifies its title, king of the birds. It has also long been associated with this time of year, making it a true winter king and a worthy bird of the month for December.

Wren

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