The mistle thrush (Turdus viscivorus) is a bird common to much of Europe, Asia and North Africa. It is a year-round resident in a large part of its range, but northern and eastern populations migrate south for the winter, often in small flocks. It is a large thrush with pale grey-brown upper parts, a greyish-white chin and throat, and black spots on its pale yellow and off-white under parts. The sexes are similar in plumage, and its three subspecies show only minimal differences. The male has a loud, far-carrying song which is delivered even in wet and windy weather, earning the bird the old name of stormcock.
Found in open woods, parks, hedges and cultivated land, the mistle thrush feeds on a wide variety of invertebrates, seeds and berries. Its preferred fruits include those of the mistletoe, holly and yew. Mistletoe is favoured where it is available, and this is reflected in the thrush's English and scientific names; the plant, a parasitic species, benefits from its seeds being excreted by the thrush onto branches where they can germinate. In winter, a mistle thrush will vigorously defend mistletoe clumps or a holly tree as a food reserve for when times are hard.
The open cup nest is built against a trunk or in a forked branch, and is fearlessly defended against potential predators, sometimes including humans or cats. The clutch, typically of three to five eggs, is incubated for 12–15 days, mainly by the female. The chicks fledge about 14–16 days after hatching. There are normally two broods. There was a large range expansion in the 18th and early 19th centuries, and a small decline in recent decades, perhaps due to changes in agricultural practices. Given its high numbers and very large range, this thrush is classified by the International Union for Conservation of Nature as being of least concern.
The mistle thrush was first described by Linnaeus in his Systema naturae in 1758 under its current scientific names.Turdus is the Latin for "thrush", and viscivorus, "mistletoe eater", comes from viscum "mistletoe" and vorare, "to devour". The bird's liking for mistletoe berries is also indicated by its English name, "mistle" being an old name for the plant.
There are more than 60 species of medium to large thrushes in the genus Turdus, characterised by rounded heads, longish pointed wings, and usually melodious songs. A mitochondrial DNA study identified the mistle thrush's closest relatives as the similarly plumaged song and Chinese thrushes; these three species are early offshoots from the Eurasian lineage of Turdus thrushes after they spread north from Africa. They are less closely related to other European thrush species such as the blackbird (T. merula) which are descended from ancestors that had colonised the Caribbean islands from Africa and subsequently reached Europe from there.
At least eight subspecies have been proposed, but the differences are mainly clinal, with birds of the nominate subspecies becoming paler and less densely spotted in the east of the range. The currently accepted subspecies are:
Turdus viscivorus viscivorus, Linnaeus, 1758. The nominate subspecies.
An isolated population in Crimea has sometimes been separated as T. v. tauricus, but this is not considered to be a valid form. Mistle thrush fossils have been found in Pleistocene deposits from Poland and Sicily.