independent

Monday 23 April 2018

Cold winters take a heavy toll on Wren population

Nature Trail - Jim Hurley

Little Jenny Wren with her cocked up tail is one of our best known wild birds. She seems to have no neck and that, in combination of her short wings, stumpy tail and diminutive size, makes her look like a small brown ball moving jerkily about.

Wrens are mainly meat-eaters feeding on insects, insect larvae, spiders and all manner of creepy-crawlies. It is a common sight to see a Wren running and fluttering around the outside of a house looking for spiders under the plinths and window sills.

Though very small, the Wren is not our smallest bird; that particular title goes to the Goldcrest, a wild bird that is not alone the smallest found in Ireland but is the smallest bird found in Europe. The Firecrest comes next in size.

Both sexes of our third smallest bird look alike and the young look like adults so there is little variation in the plumages of Wrens. In colour, they present as brownish-grey overall, more a richer reddish-brown above and a drabber whitish-brown below. The wings and tail are finely barred black and white. And they have a white eye-stripe.

The Wren is one of our most common and widespread wild birds. It is found throughout the country in a wide range of habitats. Small as it is, it has managed to colonise most of our offshore islands.

For such tiny birds, Wrens have amazingly loud even shrill songs. Like Robins they sing in winter and their metallic trilling notes, delivered with gusto, bring joy to grey days when many other birds are silent.

In summertime, the discovery of a Wren's nest hidden deep in the Ivy reveals the wonder of its construction: a sizable, stout ball of leaves, grass, moss and bits of other plant material with a round entrance hole. A male may have a number of nests in his territory with a different female in residence in each.

One of the great disadvantages of being small is that Wrens lose heat very quickly. Cold winters take a heavy toll on their tiny bodies so they need to breed quickly and efficiently to ensure that the population sustains itself.

Another survival technique is that on cold nights during the winter, they roost communally puffing out their feathers and huddling together to stay warm. Several dozen Wrens have been recorded crammed into a nest box to gain shelter from wind and rain and to benefit from each other's body heat.

Corkman

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