UKBirds

Short-Toed Treecreeper

Certhia brachydactyla

The Short-toed Treecreeper, Certhia brachydactyla, is a small passerine bird found in woodlands through much of the warmer regions of Europe and into north Africa. It has a generally more southerly distribution than the other European treecreeper species, the Common Treecreeper, with which it is easily confused where they both occur. Short-toed Treecreeper tends to prefer deciduous trees and lower altitudes than its relative in these overlap areas. Although mainly sedentary, vagrants have occurred outside the breeding range.

Short-toed Treecreeper is one of a group of four very similar Holarctic treecreepers, including the closely related North American Brown Creepers, and has five subspecies differing in appearance and song. Like other treecreepers, Short-toed is inconspicuously plumaged brown above and whitish below, and has a curved bill and stiff tail feathers. It is a resident in woodlands throughout its range, and nests in tree crevices or behind bark flakes, laying about six eggs. This common, unwary, but inconspicuous species feeds mainly on insects which are picked from the tree trunk as the treecreeper ascends with short hops.

All the treecreepers are similar in appearance, being small birds with streaked and spotted brown upperparts, rufous rumps and whitish underparts. They have long decurved bills, and long stiff tail feathers which provide support as they creep up tree trunks looking for insects.

The Short-toed Treecreeper is 12.5 centimetres (5 in) long and weighs 7.5-11 grams (0.26-0.39 oz). It has dull grey-brown upperparts intricately patterned with black, buff and white, a weak off-white supercilium and dingy underparts contrasting with the white throat. The sexes are similar, but juveniles have whitish underparts, sometimes with a buff belly.

The call of this species is a repeated shrill tyt...tyt tyt-tyt and the song of the nominate subspecies is an evenly spaced sequence of notes teet-teet-teet-e-roi-tiit. There is some geographical variation; the song of Danish birds is shorter, that of the Cyprus subspecies is very short and simple, and the North African version is lower pitched. European birds do not respond to latter two song variants.

This species shares much of its range with the Common Treecreeper. Compared to Short-toed, that bird is whiter below, warmer and more spotted above, and has a whiter supercilium and slightly shorter bill. However, identification by sight may be impossible for poorly-marked birds. Vocal birds are usually identifiable, since Common has a distinctive song composed of twitters, ripples and a final whistle and a shree' call rarely given by Short-toed; however, both species have been known to sing the other's song. Even in the hand, although Short-toed usually has a longer bill and shorter toes, 5% of birds are not safely identifiable.

Brown Treecreeper has never been recorded in Europe, but would be difficult to separate from Short-toed Treecreeper, which it much resembles in appearance. Its call is more like Common Treecreeper's, but a vagrant Brown Treecreeper might still not be possible to identify with certainty given the similarities between the three species.

The Short-toed Treecreeper breeds in temperate woodlands across Europe from Portugal to Turkey and Greece, and in north west Africa. It prefers well-grown trees, especially oak and avoids pure stands of conifers. Where it shares its European range with Common Treecreeper, the latter species tends to be found mainly in coniferous forest and at higher altitudes.

It is usually found in the lowlands, but breeds locally at up to 900 metres (2950 ft) in Germany, 1800 metres (5900 ft) France and 1400 metres (4590 ft) in Switzerland. In Turkey and North Africa it is a mountain species. The breeding areas have July isotherms between 17-18 oC and 26 oC (63-64 oF and 79 oF).

This treecreeper is essentially non-migratory but post-breeding dispersal may lead to vagrancy outside the normal range. It has occurred as a vagrant to England, Sweden, Lithuania and the Balearic Islands. Three birds on Corsica in 1969 appeared to be of the North African subspecies C. b. mauritanica.

This species has an extensive range of between 1-10 million square kilometres (0.4-3.8 million square mi). It has a large population, estimated at between 4.1-14 million individuals. Population trends have not been quantified, but the species is not believed to approach the thresholds for the population decline criterion of the IUCN Red List (declining more than 30% in ten years or three generations). For these reasons, the Short-toed Treecreeper is evaluated as Least Concern.

It is common through much of its range, but is rare in the Caucasus and on the smaller Channel Islands. In the west of its range it is spreading north through Denmark, where it first bred in 1946.