Nature Table - WREN

(Troglodytes troglodytes)

The wren isn’t Ireland’s smallest bird but it is the most widespread. There would be even more of them except for the fact there is high mortality during harsh winter weather.

Wrens eat small invertebrates such as insects, spiders and mites and don’t diversify to a vegetarian diet in winter, as many other small birds do.

This leaves them vulnerable to food shortages and their small size makes them even more vulnerable to hypothermia.

A small number escape the dangers by migrating. The birds that stay behind often use their domed nests to roost in on cold nights, something rather unusual in the bird world. And, although they’re normally territorial they forget their differences in a cold snap and huddle together for warmth.

One cold February night in England 61 wrens were found to be sleeping together in a disused nest box.