The short-toed treecreeper (Certhia brachydactyla) is a small passerinebird 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,[2] 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.[3] 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.[4]
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.[2]
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:[5]
Similar to C. b. megarhyncha, but duller rufous upperparts.
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.[5]
The short-toed treecreeper is 12.5 centimetres (4.9 inches) long and weighs 7.5–11g (0.26–0.39oz). 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.[5]
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.[5]
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.[5]
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.[7]
It is usually found in the lowlands, but breeds locally at up to 900 metres (3,000 feet) in Germany, 1,800 metres (5,900 feet) in France and 1,400 metres (4,600 feet) in Switzerland. In Turkey and North Africa it is a mountain species.[5] The breeding areas have July isotherms between 17–18°C and 26°C (63–64°F and 79°F).[7]
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.[5]
Behaviour and ecology
Breeding
Eggs of Certhia brachydactylaMHNTAdult foraging on a trunk
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.[5]
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 or spider web. The eggs are laid between April and mid June (typical clutch 5–7 eggs); they are white with purple-red blotches, 15.6mm ×12.2mm (0.61in ×0.48in) in size. The eggs are incubated by the female alone for 13 – 15 days until the altricial downy chicks hatch; they are then fed by both parents, but brooded by the female alone, for a further 15 – 18 days to fledging.[7] This species often raises a second brood. The male starts constructing a new nest while the female is still feeding the first brood, and when the chicks are 10–12 days old, he takes over feeding duties while the female completes the new nest.[5]
A Spanish study suggests that forest fragmentation adversely affects the numbers of short-toed treecreepers present, as is also the case with the common treecreeper. Species that depend on relatively scarce resources, such as tree trunks, only occupy the larger forests, whereas those such as tits and common firecrests that exploit abundant, ubiquitous resources are distributed uniformly through woodlands of all sizes.[8][9]
Feeding
The short-toed treecreeper typically seeks invertebrate food on tree trunks, starting near the tree base and spiralling its way up using its stiff tail feathers for support. Unlike a nuthatch, it does not come down trees head first, but flies to the base of another nearby tree. It uses its long thin bill to extract insects and spiders from crevices in the bark. Although normally found on trees, it will occasionally feed on walls or bare ground, or amongst fallen pine needles. It may add some seeds to its diet in the colder months.[7]
Habits
As a small woodland bird with cryptic plumage and a quiet call, the short-toed treecreeper is easily overlooked as it hops mouse-like up a vertical trunk, progressing in short hops, using its stiff tail and widely splayed feet as support. Nevertheless, it is not wary, and is largely indifferent to the presence of humans. It has a distinctive erratic and undulating flight, alternating fluttering butterfly-like wing beats with side-slips and tumbles. It is solitary in winter, but in cold weather up to twenty or more birds will roost together in a suitable sheltered crevice, or in a star formation under eaves of buildings.[5]
Status and conservation
This species has an extensive range of between 1–10million square kilometres (0.4–3.8million 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.[1]
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.[5]
Related Research Articles
The nuthatches constitute a genus, Sitta, of small passerine birds belonging to the family Sittidae. Characterised by large heads, short tails, and powerful bills and feet, nuthatches advertise their territory using loud, simple songs. Most species exhibit grey or bluish upperparts and a black eye stripe.
The treecreepers are a family, Certhiidae, of small passerine birds, widespread in wooded regions of the Northern Hemisphere and sub-Saharan Africa. The family contains ten species in two genera, Certhia and Salpornis. Their plumage is dull-coloured, and as their name implies, they climb over the surface of trees in search of food.
The Indian spotted creeper is a small passerine bird, which is a member of the subfamily Salpornithinae which is placed along with the treecreepers in the family Certhiidae. This small bird has a marbled black and white plumage that makes it difficult to spot as it forages on the trunks of dark, deeply fissured trees where it picks out insect prey using its curved bill. It is found in patchily distributed localities mainly in the dry scrub and open deciduous forests of northern and central peninsular India. It does not migrate. Their inclusion along with the treecreepers is not certain and some studies find them more closely related to the nuthatches while others suggest a close relation to the wallcreeper. They lack the stiff tail feathers of treecreepers and do not use their tail for supporting them while creeping vertically along tree trunks.
The Eurasian treecreeper or common treecreeper is a small passerine bird also known in the British Isles, where it is the only living member of its genus, simply as treecreeper. It is similar to other treecreepers, and has a curved bill, patterned brown upperparts, whitish underparts, and long stiff tail feathers which help it creep up tree trunks. It can be most easily distinguished from the similar short-toed treecreeper, which shares much of its European range, by its different song.
The white-breasted nuthatch is a species of bird in the nuthatch family Sittidae. It is a medium-sized nuthatch, measuring approximately 15.5 cm (6.1 in) in length. Coloration varies somewhat along the species' range, but the upperparts are light blue-gray, with a black crown and nape in males, while females have a dark gray crown. The underparts are whitish, with a reddish tinge on the lower abdomen. The white-breasted nuthatch is a noisy bird. It has a nasal voice and often utters little cries or vocalizations, often composed of repetitions of small invariant whistles. In summer, it is an exclusively insectivorous bird, consuming a wide range of arthropods, but in winter its diet consists mainly of seeds. The nest is located in the cavity of a tree. The clutch consists of five to nine eggs, incubated for two weeks by the female, who is fed by the male. The two adults then feed the young until they fledge, and for a few weeks after that.
The brown creeper, also known as the American treecreeper, is a small songbird, the only North American member of the treecreeper family Certhiidae.
The white-throated treecreeper is an Australian treecreeper found in the forests of eastern Australia. It is unrelated to the northern hemisphere treecreepers. It is a small passerine bird with predominantly brown and white plumage and measuring some 15 cm (6 in) long on average. It is insectivorous, eating mainly ants. Unlike treecreepers of the genus Climacteris, the white-throated treecreeper does not engage in cooperative breeding, and wherever it overlaps with species of that genus, it feeds upon much looser bark besides typically using different trees.
Certhia is the genus of birds containing the typical treecreepers, which together with the African and Indian spotted creepers make up the family Certhiidae.
The brown treecreeper is the largest Australasian treecreeper. The bird, endemic to eastern Australia, has a broad distribution, occupying areas from Cape York, Queensland, throughout New South Wales and Victoria to Port Augusta and the Flinders Ranges, South Australia. Prevalent nowadays between 16˚S and 38˚S, the population has contracted from the edges of its pre-European range, declining in Adelaide and Cape York. Found in a diverse range of habitats varying from coastal forests to mallee shrub-lands, the brown treecreeper often occupies eucalypt-dominated woodland habitats up to 1,000 metres (3,300 ft), avoiding areas with a dense shrubby understorey.
Hodgson's treecreeper is a small passerine bird from the southern rim of the Himalayas. Its specific distinctness from the common treecreeper was recently validated.
The African spotted creeper is a small passerine bird, which is a member of the subfamily Salpornithinae of the treecreeper family Certhiidae. It is found in sub-Saharan Africa in open deciduous forest and mango groves. It does not migrate other than local movements.
↑ Charalambidou, Iris; Sparrow, David J; Stapley, John; Richardson, Colin (2016). Sparrow, David J; John, Eddie (eds.). An Introduction to the Wildlife of Cyprus. Terra Cypria. ISBN978-9963-601-45-5.
↑ Tellería, J. L.; Santos, T. (1995). "Effects of forest fragmentation on a guild of wintering passerines: The role of habitat selection". Biological Conservation. 71 (1): 61–67. doi:10.1016/0006-3207(94)00021-H.
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