How many of you have seen a treecreeper? Not too many I suspect. And with good reason because although it is by no means rare it is among our best concealed birds. This, coupled with its unusual lifestyle, makes it hard to spot. Just lately we have had an odd bird, and sometimes a pair, visiting the big lime tree in the garden. The tree is part of a long planted avenue, and I suppose in the bird mind would pass for a linear woodland. They are not confined to woodland. I have quite often found them on solitary willow trunks on the river banks.
As suggested by its name the treecreeper is a tree trunk specialist. Mid-way in size between a blue and a great tit it is mouse brown with lighter streaks above, contrasting with a startling silvery-white on the underparts. Like the woodpeckers, to which they are not related, they cling vertically to a tree trunk using their extra large feet, and use the stiff tail feathers as an extra prop to support them. They run swiftly upwards and across the trunk, looking very mouse-like as they do so. Their slender though strong beak is curved downwards like a cobbler’s awl, and they use it deftly to winkle out delicacies like spiders and their egg-balls, and insects that hide in crevices in the bark.
Quite often, during the colder months, they join up with the wandering bands of tits as they pass through their territories. So if you cannot wait to spot a treecreeper it is a good idea to scan nearby tree trunks whenever these mixed parties turn up. If luck is with you there may be one or more of them busily searching for food.
Treecreepers nest behind bits of loose bark or in crevices on tree trunks, sometimes behind ivy stems which have become detached from the trunk. Once I found a nest behind a notice board that had been nailed to a tree in a local woodland. The nest is made of roots, twigs, and flakes of bark, cosily lined with feathers and scraps of wool. Six eggs are laid, white with spots and flecks of brown, and take about eighteen days to hatch. Both adults feed the young in the nest for about a fortnight, before they fly, when they are just like short-tailed miniatures of their parents.
To me one of the treats in store whilst watching these little birds is the way their undersides flash silvery-white as they pass around the trunk and are momentarily seen sideways on.
According to the most recent surveys treecreeper numbers are thought to be slowly increasing. It remains to be seen what effects the recent severe weather and snowfalls have had on them. Certainly the ones in my garden seem to have survived.