Carbonero Palustre

Identificación

The nominate race has a black cap and nape with a blue sheen visible at close quarters. The black 'bib' below the bill is rather small; the cheeks are white, turning dusky brown on the ear coverts. The upperparts, tail and wings are greyish-brown, with slightly paler fringes to the tertials. The underparts are off-white with a buff or brown tinge strongest on the flanks and undertail coverts. The bill is black and the legs dark grey. Juveniles are very similar to adults, but with a duller black cap and bib, more greyish upperparts and paler underparts; they moult into adult plumage by September.<p>The marsh tit weighs 12 g (0.42 oz), has a length of 11.5 to 12 cm (4.5 to 4.7 in) (from bill to tail) and a wingspan of 19 cm (7.5 in). The wing length ranges from 60–70 mm (2.4–2.8 in). The oldest recorded marsh tit in Europe reached the age of 11 years, 11 months.<p>Like other tits it has a large range of call notes; most typical is the explosive "pitchou" note, given when agitated, often leading into "pitchou-bee-bee-bee", which can sound like willow tit when not heard clearly. Unlike many other tits, however, the marsh tit has a well-defined song and a wide song repertoire. Individual birds can have more than five songs, which they use interchangeably. Some of the more common songs include a typical tit-like, ringing, "schip-schip-schip-schip-ship", a more liquid "tu-tu-tu-tu-tu" and sometimes a sweet "tyeu-tyeu-tyeu-tyeu-tyeu". The old Staffordshire name for the species, 'Saw Whetter', refers to the bird's scolding call.<p>Marsh and willow tits are difficult to distinguish on appearance alone; the races occurring in the UK (P. p. dresseri and P. m. kleinschmidti respectively) are especially hard to separate. When caught for ringing, the pale 'cutting edge' of the marsh tit's bill is a reliable criterion; otherwise, the best way to tell apart the two species is by voice. Plumage characteristics include the lack of a pale wing panel (formed by pale edges to the secondary feathers in the willow tit), the marsh tit's glossier black cap and smaller black 'bib', although none of these is 'completely reliable'; for example, juvenile marsh tits can show a pale wing panel. The marsh tit has a noticeably smaller and shorter head than the willow tit and overall the markings are crisp and neat, with the head in proportion to the rest of the bird (willow tit gives the impression of being 'bull-necked').<p>A measure of the difficulty in identification is given by the fact that, in the UK, the willow tit was not identified as distinct from marsh tit until 1897. Two German ornithologists, Ernst Hartert and Otto Kleinschmidt, were studying marsh tit skins at the British Museum and found two wrongly-labelled willow tits amongst them (two willow tit specimens were then collected at Coalfall Wood in Finchley, north London, and that species was added to the British list in 1900).

Taxonomía

The marsh tit was formally described by the Swedish naturalist Carl Linnaeus in 1758 in the tenth edition of his Systema Naturae under the binomial name Parus palustris. It is now placed in the genus Poecile that was erected by the German naturalist Johann Jakob Kaup in 1829. The genus name, Poecile, is the Ancient Greek name for a now unidentifiable small bird, and is perhaps derived from poikolos, meaning "spotted"; the specific palustris is Latin for "marshy".<p>An analysis of mitochrondrial DNA sequences has shown that the marsh tit belongs to a group of Eurasian 'typical chickadees' that includes the willow tit, Père David's tit, the black-bibbed tit, and the Songar tit.<p>Ten subspecies are recognised:

Nombre científico

Poecile palustris

Autoridad

(Linnaeus, 1758)

Orden

Passeriformes

Familia

Páridos

Género

Poecile

Distribución y hábitat

The marsh tit has a worldwide Extent of Occurrence of around 10 million square kilometres. The global population includes between 6.1 million and 12 million birds in Europe alone. The species is classified as Least Concern, though there is some evidence of a decline in numbers. For example, between the 1970s and 2007, marsh tit numbers declined in the United Kingdom by more than 50% and consequently it is on the Red List of species compiled by the UK's Joint Nature Conservation Committee. Research suggests that the cause may be low survival rates from year to year, though the nest failure rate has fallen during the decline. Other studies have shown that reduced diversity of woodland structure and plant species, partly because of the impact of deer browsing, is the cause of the bird's decline.<p>Data from 157 woodlands covered by the RSPB/BTO Repeat Woodland Bird Survey showed that the abundance of marsh tits in 2003–2004 corresponded with the vegetation present 2–4 metres above the ground, the shrub layer. Data from the 1980s did not show the same results, but marsh tit numbers had increased by 2003–2004 in woods with the most shrub cover. The study concluded that damage to the shrub layer, caused by overgrazing by deer, for example, may make woodland less suitable for marsh tits.<p>It is a widespread and common resident breeder throughout temperate Europe and northern Asia. It occurs from northern Spain north to south-eastern Scotland and east to western Russia, with a broad gap in western Asia and present again in eastern Asia from the Altai Mountains east to northern Japan and northern and western China.<p>This species is sedentary, making short post-breeding movements in most of its range, but in northern Europe some move southward in winter. However, marsh tits seem not to perform the occasional irruptions that other members of the tit family do. Most marsh tits stay in their breeding territories year-round; presumably this is related to their food-storing strategy. Analysis of UK ringing data showed that of 108 recoveries (when a ringed bird is found dead or caught by another ringer), 85% were less than 5 km from where the bird was originally caught, and only 1% further than 20 km. Young birds join mixed roaming flocks; adults also join the flocks when they pass through, but do not stray from their territory.<p>Marsh tits breed mostly in lowland areas, but can reach altitudes of up to 1,300 m. They prefer large areas of moist, broadleaved woodland, often oak or beech, though they can occupy wet alder woodland, riverside trees, parks and gardens or orchards. A study at Monks Wood, Cambridgeshire, England, found that marsh tits required mature trees with a shrub layer below the canopy, but that they avoided parts of the wood with many young trees. Another study in the United Kingdom found that during winter and while foraging, marsh tits spent more time than blue tits in the wood's understorey, and more time lower in the woodland canopy and understorey. Trees and shrubs in 10 breeding territories were also compared. The trees varied significantly between territories, but the shrub characteristics did not, suggesting that the shrubs were more important to the birds. In Wytham Woods, Oxfordshire, marsh tits were "largely absent" from parts of the wood with a dense canopy but poor shrub cover.

Migración

Especie residente

Comportamiento

Patrón migratorio: Especie residente.

Conservación

Tendencia poblacional: en declive.

Tendencia poblacional

en declive