Treecreeper (Certhia familiaris)
This can be an elusive species to find on Barnes Common but is a delightful bird to see. The Treecreeper is resident in the UK and a classic woodland bird, depending on trees for every part of its life.
It is generally very active, with speckled brown plumage above and clean white below. A long, slender, down-curved bill is ideally adapted for probing into small crevices to find insects while very large feet with sharp, arched claws and a stiff tail to support their weight, makes them adept climbers. For this reason, Treecreepers are generally always seen going upwards and will fly downward to the base of the next tree once they reach the top of the last one.
They are peculiarly mouse-like, often moving around a tree in upward spirals and usually on the other side of the tree to the viewer! They have been found sleeping in small cavities, hollows or shallow depressions within the bark of a tree where they are superbly camouflaged.
At this time of year, Treecreepers will be feeding their young but their nests can be prone to predation by Great Spotted Woodpecker. However, FoBC has put up a number of purpose built boxes for them which should afford some security.
In autumn and winter, Treecreepers often join flocks of tits and other small birds, so if you come across such a flock in a wood, it is worth looking out for a flash of white before a bird alights at the bottom of a tree.