The Eurasian wren (Troglodytes troglodytes) is the UK’s commonest breeding bird, with an estimated 11 million breeding pairs. This sweet, diminutive bird has an elaborate and exuberant song that echoes among its woodland habitats. This is a guide to wren nesting in the UK.
Wrens are common across the UK’s deciduous forests. Their nests are small, neat domes measuring just a few inches across and are found in small tree cavities, among brambles, hedges, and other natural or synthetic cavities.
The Eurasian wren is typically found in lowlands, heathlands, farmlands, and forested grasslands and is less common in the uplands of Scotland and parts of northern England and Wales.
Despite being the UK’s most common breeding bird, they’re not easy to spot due to their tiny size and shy nature. Also, wrens are constantly on the move, so if you do see one, it might disappear in the blink of an eye!
There is much more to learn about the nesting behaviour of this wonderful small bird - read on to find out!
Wren nesting inside of a cavity
Wrens in the UK nest in a wide range of habitats, including woodland, farmland, heathland, moorland, and some coastal and island environments.
While they generally prefer coniferous woodlands in mainland Europe, the UK’s wren population commonly inhabits deciduous woodlands. They also inhabit coniferous pine forests across northern England, Scotland and Wales.
Wrens prefer lowland habitats and are less common in upland environments, but generally speaking, they’re common throughout the entire UK, including most of its surrounding islands stretching from the Shetlands to the Isle of Wight.
Most wrens are found in deciduous woodland, and they’re less abundant in Scotland and northern England, with the smallest numbers found in remote upland areas like the Scottish Highlands.
They are a regular visitor to many gardens but aren’t easy to spot due to their small size and shy, fast-moving nature.
In the early spring, the male wren proceeds to build multiple nests in his breeding territory called “cock nests”. The female prefers to mate with males with more nests.
Once paired, the female will help the male line the chosen nest. Breeding territories are maintained from year to year, but the pair would rarely reuse nests. However, wrens raise two or three broods per year, and they might reuse the same nest from brood to brood.
Wren peeking out of their nest
Wrens certainly do nest in gardens, especially if they’re relatively well-covered with dense foliage and trees.
Wrens generally nest off the ground in trees or bushes around 1m to 5m off the ground and prefer tree cavities, but they also nest in foliage. Well-foliaged gardens with plenty of food and no domestic cats or other predators are more likely to attract wrens.
Wrens use bird boxes with large entrances of some 10 to 15cm. You can buy special wren nesting boxes that also suit robins and other tiny birds.
Wren bird boxes have larger open entrances than the small holed bird boxes preferred by Blue tits and small songbirds.
Wrens nest in a variety of different trees, so long as there’s an eligible cavity at a height of around 1m up to a maximum height of around 10m.
Ancient deciduous woodland yields many choices, such as oaks and beeches, and wrens also nest in coniferous forests with pines and fir trees. They’re not fussy regarding the exact species of tree they nest in, so long as there’s a small, cosy cavity.
Wrens also nest in rocks and the crevices of ruined human buildings. A few wren nests have been found in unusual places, such as old boots or coat pockets. This is much more common in the US, e.g. the Carolina wren frequently nests in synthetic human items.
Wren bringing nesting materials to a nest box
Wren nests are neat and compact domes with a side entrance. They’re built from various mosses, soft foliage, twigs, leaves, grass and lichen that are compressed into small holes and recesses.
The resulting dome is lined generously with feathers, soft mosses and synthetic fibres if available. They look small and intricate but are tough to spot due to their small, compact size.
The completed nest looks cosy and warm - there’s not much room for the chicks when they hatch!
The wren itself is around 10cm long, and the nest isn’t much larger than the bird itself.
The average wren nests are approximately 11.3cm high, 13cm wide and 14.5 cm deep. The internal chamber is around 6.2cm in diameter and 5.6.cm high.
Some wren nests can be compressed into spaces of around 15cm deep or so. There’s only enough room for one adult bird - the mother - who incubates the chicks independently.
The nest of a Eurasian Wren, with three young chicks inside
Wrens start breeding in mid to late April, but nest construction begins sometime before.
In some warmer southern regions of the UK, nesting starts as early as March, but in the north, wrens might prolong it until June and July.
Before the start of the breeding season, the male will have constructed several basic nests in his breeding territory. The male and female then pick one nest to complete before copulation and egg laying.
Wrens have a relatively long breeding season that lasts until as late as early August in a mild year.
Some wrens have three broods a year, but this is rare - two is much more common.
Egg laying typically gets underway in late April but may be earlier in the south and later in the north. Second broods are raised in late June and July.
Close up of a Wren gathering nesting materials
Sometime before the start of spring in late winter, the male wren starts building nests in his breeding territory. These ‘draft’ nests are called “cock nests” and help the male attract female partners. The male might build as many as 12 nests in his territory!
When the female comes to the male’s territory, he will sing to her and display to her before she chooses a nest for them to finish. The female lines the chosen nest with feathers prior to copulation.
Cavities are popular places for Wrens to nest in
Wren eggs are tiny, measuring approximately 16.6 by 12.7 mm (0.65 by 0.50 in). They are mainly white with varying amounts of reddish-brown speckles concentrated towards the broader end.
Wrens lay relatively large clutches of 5 to 6 eggs on average. Clutches as large as 10 or 11 eggs have been observed, but this is exceptionally rare.
Some nests have been found with as many as 17 eggs, though this likely resulted from two females laying in the same nest. Interestingly, island subspecies, such as the Shetland wren, are observed to lay smaller clutches.
The female exclusively incubates the eggs, and the male may leave relatively swiftly to find another female as he is polygamous.
However, the male does help feed the young nestlings, which is a pretty intensive job if he’s raising two, three or even four families at once!
A perched Wren singing during the spring
Baby wrens fledge after around 12 to 18 days but may leave earlier if the nest is disturbed. The parents withhold food to encourage the chicks to leave and forage food for themselves.
Their parents continue to feed the young birds for a week or two after they leave the nest but eventually abandon the young birds and let them fend for themselves.
Wrens commonly raise one to two broods, but three broods have been recorded. This is rare in the UK and more common in southern Europe.
The female wren takes care of incubation, but both the male and female feed the young through until independence, which takes a total of around 30 days.
Wren feeding spider and grubs to a baby chick in a garden nest box
Like most birds, wrens typically only abandon their nest if it’s seriously threatened or partially destroyed.
The Eurasian wren doesn’t usually nest on the ground and prefers trees and hedges around 1m to 10m off the ground.
In the winter, wrens roost in the abandoned nest cavities of other birds and empty nest boxes. Wrens tend to roost communally, and as many as 40 have been found roosting together in a large bird box!
Wren nestling success in one study was around 40%. Some 91% of nests failed due to predation. Nests face threats from virtually all land predators and many predatory or aggressive birds. Nests are sometimes parasitized by cuckoos.
Eurasian Wren fledgling exploring the forest
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