February 2026 – A Bundle of Winter Wrens
By Kerry Williams: Communications Officer – Conservation, Sussex Wildlife Trust
Someone once told me if you think you’ve seen a mouse it’s probably a Wren. These diminutive brown birds make a habit of hopping about the undergrowth in stop-motion fashion, feeding on insects, spiders, and occasionally berries and seeds. Despite being the UK’s most numerous breeding bird, they can be inconspicuous.
The similarity promptly ends when they open their mouth. Though weighing under 10g, the Wren’s voice is bold and loud; a long, high-pitched whistle and trill, cutting through crisp morning air and reaching above that of larger songsters. If you watch a Wren singing, you’ll notice the effort on its small body – beak wide and tail upturned.
Woodland understory is an ideal nesting habitat for Wrens, and males establish clear territories in early spring, using that powerful voice. They build five or even six nests to try and attract a female and will aggressively deter other males that dare approach.
However, when the chill of winter comes around, the male changes his tune. A balmy summer of successful shouting may have shown that a tiny body is no barrier to being heard, but it won’t help with heat loss on cold nights.
So, the male starts collecting bedfellows. Flitting out on short trips, he again utilises his song, letting females and other males know they are welcome to join him for a platonic sleepover, starting after dusk and ending before dawn.
“Oh, that stuff I said in spring? Water under the bridge.”
They gratefully accept, bundling into moss and leaf-lined woven grass, squidging tiny wings and bellies together to make room for just one more. Beaks in, bums out. Most consist of small gatherings, but records of dozens have been logged, and one count in the 1960s numbered 61 Wrens.
Not just super cute, the warmth-sharing of these communal roosts might be lifesaving. Although as anyone who shares a bed will know, there can be a waste of energy caused by the wriggling of others. Shuffling for space, preening, defecating in the roost; entirely unacceptable sleepover etiquette.
When warmer days thankfully return it’s back to spring rules, and the male begins to banish other males from the roost, cosy winter cuddles forgotten until the cold starts to nip around tiny feet once more.
Next time you hear a winter Wren having a good yell, be sympathetic. It’s survived the night, thank goodness, but it’s had a terrible night’s sleep.