The willow tit (Poecile montanus ) is a passerine bird in the tit family, Paridae. It is a widespread and common resident breeder throughout temperate and subarctic Europe and across the Palearctic. The plumage is grey-brown and off-white with a black cap and bib. It is more of a conifer specialist than the closely related marsh tit, which explains it breeding much further north. It is resident, and most birds do not migrate.
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TerrestrialTerrestrial animals are animals that live predominantly or entirely on land (e.g., cats, ants, snails), as compared with aquatic animals, which liv...
Oviparous animals are female animals that lay their eggs, with little or no other embryonic development within the mother. This is the reproductive...
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Partial MigrantPartial migration is when within a migratory species or even within a single population, some individuals migrate while others do not.
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starts withThe willow tit is 11.5 cm (4.5 in) in length, has a wingspan of 17–20.5 cm (6.7–8.1 in) and weighs around 11 g (0.39 oz).
In the east of its range it is much paler than marsh tit, but as one goes west the various races become increasingly similar, so much so that it was not recognised as a breeding bird in Great Britain until the end of the 19th century, despite being widespread.
The willow tit is distinguished from the marsh tit by a sooty brown instead of a glossy blue black cap; the general colour is otherwise similar, though the under parts are more buff and the flanks distinctly more rufous; the pale buff edgings to the secondaries form a light patch on the closed wing. The feathers of the crown and the black bib under the bill are longer, but this is not an easily noticed character. However, the more graduated tail (not square) shows distinctly when spread.
The commonest call is a nasal zee, zee, zee, but the notes of the bird evidently vary considerably. Occasionally a double note, ipsee, ipsee, is repeated four or five times.
Birds feed on insects, caterpillars, and seeds, much like other tits. This species is parasitised by the moorhen flea, Dasypsyllus gallinulae.
The willow tit excavates its own nesting hole, even piercing hard bark; this is usually in a rotten stump or in a tree, more or less decayed. Most nests examined are cups of felted material, such as fur, hair and wood chips, but feathers are sometimes used. The number of eggs varies from six to nine, with reddish spots or blotches.
In a study using ring-recovery data carried out in northern Finland, the survival rate for juveniles for their first year was 0.58, and the subsequent adult annual survival rate was 0.64. For birds that survive the first year the typical lifespan is thus only three years. The maximum recorded age is 11 years; this has been recorded for a bird in Finland and for another near Nottingham in England.
The willow tit has an extremely large range with an estimated population of between 175 and 253 million mature individuals. This large population appears to be slowly decreasing but the decline is not sufficiently rapid to approach the threshold of vulnerability. The species is therefore classed as of least-concern by the International Union for Conservation of Nature. In contrast, the number in the United Kingdom declined by 83% between 1995 and 2017. There was also a contraction in the range. The rapid decline is believed be due to three factors: habitat loss, competition for nest holes by other tits particularly blue tits, and nest predation by the great spotted woodpecker. Over the same period, the number of great spotted woodpeckers increased fourfold.
