Parus palustris

The marsh tit (Poecile palustris) is a passerine bird in the tit family Paridae and genus Poecile, closely related to the willow, Père David's and Songar tits. It is small (around 12 cm long and weighing 12 g) with a black crown and nape, pale cheeks, brown back and greyish-brown wings and tail. Between 8 and 11 subspecies are recognised. This bird's close resemblance to the willow tit can cause identification problems, especially in the United Kingdom where the local subspecies of the two are very similar (there, they were not recognised as separate species until 1897). Globally, the marsh tit is classified as Least Concern, although there is evidence of a decline in numbers (in the UK, numbers have dropped by more than 50% since the 1970s, for example). It can be found throughout temperate Europe and northern Asia and, despite its name, it occurs in a range of habitats including dry woodland. The marsh tit is omnivorous; its food includes caterpillars, spiders and seeds. It nests in tree holes, choosing existing hollows to enlarge, rather than excavating its own. A clutch of 5–9 eggs is laid. 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'. 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. Ten subspecies are recognised: Nominate race palustris: 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. The marsh tit weighs 12 g, is 11.5 to 12 cm long (from bill to tail) and the wingspan is 19 cm. Wing length ranges from 60–70 mm. The oldest recorded marsh tit in Europe reached the age of 11 years, 11 months. Marsh and willow tits are difficult to identify 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').