Eurasian treecreeper  (Certhia familiaris)

The Eurasian treecreeper is classified as Least Concern (LC) on the IUCN Red List (1).

A small, slim, mouse-like bird, the Eurasian treecreeper (Certhia familiaris) has a downward-curved, highly pointed bill which it uses to probe crevices in tree bark in search of prey (2). This species gains its common name from its method of finding food, in which it will seemingly ‘creep’ up trees using its long claws and stiff tail to assist its ascent (2).

The upperparts of the Eurasian treecreeper are finely speckled white and brown, and contrast with the completely white underside. It also has two brown-white wing-bars and the undersides of the wings are silvery-white (3). There is a small white stripe behind the eye (2). The male and female Eurasian treecreeper are similar in appearance, while juveniles have a duller, less distinctive colouration (4).

The song of the Eurasian treecreeper is extremely high pitched, at times being completely inaudible to humans (2).

The distribution of the Eurasian treecreeper extends from Britain to Japan (2), including the Mediterranean, Middle East and parts of Asia, but excluding India and the Philippines (2).

This species is a partial migrant, meaning it will only migrate when its food source becomes scarce in winter. Generally, the Eurasian treecreeper will only migrate short distances, usually moving only as far as the nearest available food source (5).

A woodland bird, the Eurasian treecreeper tends to favour high altitudes and is mostly found in coniferous forests (2). It can also be found in deciduous and mixed woodland where there are trees with loose, rough bark (5).

The Eurasian treecreeper is a weak flier and can often be seen creeping in a spiral up tree trunks in search of food. Once it has ascended a tree, it will move on to the base of the next, only climbing part way up each tree. The stiff tail of the Eurasian treecreeper provides support during this manoeuvre, and its long claws also help to grip the bark while it forages for its prey. The Eurasian treecreepers diet consists mainly of insects, spiders, as well as their eggs and larvae (2).

During the night, the Eurasian treecreeper roosts underneath the soft or dead bark of trees, fluffing its feathers to keep warm. During winter months, when the temperature is greatly reduced, groups of up to 15 birds will gather together in the same roost. However, at other times, the Eurasian treecreeper is very territorial and will attack if another bird comes too close to its roost or nest (2).

During courtship, the male Eurasian treecreeper will fly in spirals around the branch or trunk that the female is perched on, or will chase the female around the trunks of trees, in a way not dissimilar to its method of finding food (2).

The Eurasian treecreeper builds its nest in the same place as its roost. The nest is usually made of grass, moss and leaves and there is a central depression which holds the eggs, comprising a combination of feathers and bark (2). The Eurasian treecreeper usually has two broods of five to six eggs a year, which are mainly incubated by the female. The female is sometimes helped by the male, although the male does not have the same featherless brood patch on its breast (3). The eggs are incubated for around 13 to 15 days and the chicks remain in the nest until they are around 18 days old. The chicks are fed by both adult Eurasian treecreepers until they fledge (2).

The Eurasian treecreeper has a very large population and is not believed to be under threat of extinction (6).

There are currently no specific conservation measures known to be in place for the Eurasian treecreeper.

Find out more about the Eurasian treecreeper:

• Birdlife International - Eurasian treecreeper:
  http://www.birdlife.org/datazone/speciesfactsheet.php?id=32439