Treecreeper

From British Birds: The Common Treecreeper is like a feathered mouse which discretely climbs in spirals up the trunk of one tree before flying down to start on the next one. Its speckled brown plumage provides excellent camouflage but the silvery-white underparts may give it away. Other features to look for are its long pale eyestripes, slender down-curved bill and black-edged golden wing-bar sometimes glimpsed as it flies.