treecreeper

The treecreepers are a family, Certhiidae, of small passerine birds, widespread in wooded regions of the Northern Hemisphere. The family contains nine species in one genus, Certhia. Their plumage is dull-coloured. As their name implies, they climb over the vertical surfaces of trees in search of food.

==Taxonomy and systematics== Some taxonomists place the nuthatches and treecreepers in a larger grouping with the wrens and gnatcatchers. This superfamily, the Certhioidea, was based on phylogenetic studies using mitochondrial and nuclear DNA, and was created to cover a clade of four families removed from a larger grouping of passerine birds, the Sylvioidea. The fossil record for this group appears to be restricted to a foot bone of an early Miocene bird from Bavaria which has been identified as an extinct representative of the climbing Certhioidea, a clade comprising the treecreepers, wallcreeper and nuthatches. It has been described as Certhiops rummeli.