Short-toed treecreeper

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. The 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.

The 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, the 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.

Taxonomy

The short-toed treecreeper was first described by Christian Ludwig Brehm in 1820. The binomial name is derived from Greek; ''kerthios'' is a small tree-dwelling bird described by Aristotle and others, and ''brachydactyla'' comes from ''brakhus'', "short" and ''dactulos'' "finger", which refers, like the English name, to the fact that this species has shorter toes than the common treecreeper.

This species is one of a group of very similar treecreeper species, all placed in the single genus '' Certhia''. Eight species are currently recognised, in two evolutionary lineages, a Holarctic radiation, and a Sino-Himalayan group south and east of the Himalayas. The former group has a more warbling song, always (except in ''C. familiaris'' from China) starting or ending with a shrill ''sreeh''. The Himalayan species, in contrast, have a faster-paced trill without the ''sreeh'' sound. The short-toed treecreeper belongs to the northern group, along with the North American brown creeper, ''C. americana'', the common treecreeper, ''C. familaris'', of temperate Eurasia, and Hodgson's treecreeper, ''C. hodgsoni'', from the southern rim of the Himalayas.

Subspecies

There are five subspecies of short-toed treecreeper, which are all very similar and often intergrade in areas where their ranges overlap. There is a general cline in appearance from west to east across Europe, with upperparts becoming a darker and colder brown. The currently recognised subspecies are as follows:

Description

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 long and weighs . 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 the 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 the short-toed; however, both species have been known to sing the other's song. Even in the hand, although the short-toed usually has a longer bill and shorter toes, 5% of birds are not safely identifiable.

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

Distribution and habitat

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 in Germany, in France and in Switzerland. In Turkey and North Africa it is a mountain species. The breeding areas have July isotherms between 17–18 °C and 26 °C (63–64 °F and 79 °F). 1411–1416

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''.

Behaviour and ecology

Breeding

The short-toed nests in tree crevices or behind bark flakes. Old woodpecker nests, crevices in buildings or walls, and artificial nest boxes or flaps are also used.

The nest has an often bulky base of twigs, pine needles, grass or bark, and a lining of finer material such as feathers, wool, moss, lichen

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