The treecreepers are a family, Certhiidae, of small passerine birds, widespread in wooded regions of the Northern Hemisphere and sub-Saharan Africa, and identified by a long, slender, downcurved bill. These include: The Eurasian treecreeper or common treecreeper (Certhia familiaris) and Brown creepers (Certhia americana), the only treecreepers in North America. At first glance, treecreepers look very much like mice as they hop up tree trunks, which gives them the fitting country name: tree mouse. Unlike the nuthatch, treecreepers can't actually climb down trees, so must leap off and fly to the base of the next tree in their endless search for beetles, earwigs and woodlice to pull out of the bark. In a day they may climb 2500m (higher than any British mountain). The sexes are alike, and they build their nests in small splits caused by bark flaking away from a tree trunk.