- The typical treecreepers (Certhiinae) are a group of seven species found in Europe and Asia, with one representative, the Brown Creeper in North America.
- The Spotted Creeper Salpornis spilonotus (Salpornithinae), which is found in India and Africa.
The typical treecreepers are all very similar in appearance, and can present serious identification problems where two species occur together. They do not migrate other than for local movements.
The treecreepers are small woodland birds, brown above and white below. They have thin pointed down-curved bills, which they use to extricate insects from bark. They have stiff tail feathers, like woodpeckers, which they use to support themselves on vertical trees.
Nests are in tree crevices or behind bark.
Following recent studies of cytochrome b mtDNA sequence and song structure (Tietze et al., 2006), the following species are recognized:
- Common Treecreeper or Eurasian Treecreeper, Certhia
Hodgson's Treecreeper, Certhia hodgsoni
Brown Creeper, Certhia americana
Short-toed Treecreeper, Certhia brachydactyla
Himalayan Treecreeper or Bar-tailed Treecreeper, Certhia himalayana
Sichuan Treecreeper, Certhia tianquanensis
Nepal Treecreeper or Rusty-flanked Treecreeper, Certhia nipalensis
Sikkim Treecreeper or Brown-throated Treecreeper, Certhia discolor
Manipur Treecreeper, Certhia manipurensis
They form two evolutionary lineages: the former four species represent a Holarctic radiation, whereas the remaining five are distributed in the area south and east of the Himalaya. Hodgson's Treecreeper, recently realized to be a distinct species, is an offshoot of the Common Treecreeper's ancestor which has speciated south of the Himalaya. The former group has a more warbling song, always (except in C. familiaris from China) starting or ending with a shrill sreeh. The Himalayan group, in contrast, has a faster-paced trill without the sreeh sound.
Other birds with creeper or treecreeper in their name
There are two other small bird families with treecreeper or creeper in their name:
- the Australian treecreepers (Climacteridae)
the Philippine creepers (Rhabdornithidae)
- Tietze, Dieter Thomas; Martens, Jochen & Sun, Yue-Hua (2006): Molecular phylogeny of treecreepers (Certhia) detects hidden diversity. Ibis 148(3): 477-488 DOI:doi:10.1111/j.1474-919X.2006.00547.x (HTML abstract)
- Treecreeper videos on the Internet Bird Collection