The dunnock is a small perching bird, found throughout temperate Europe and into Asian Russia. It has a drab appearance which may have evolved to avoid predation. It is brownish underneath and has a fine pointed bill. Adults have a grey head, and both sexes are similarly colored. Unlike any similar-sized small brown bird, dunnocks frequently flick with their wings, especially during territorial disputes or when competing for mating rights. This gives rise to one of their common names, "shufflewing".
Dunnocks are native to large areas of Eurasia, inhabiting much of Europe including Lebanon, northern Iran, and the Caucasus. They are partially migratory; some populations are resident while birds in northern and eastern parts of the range are migratory. Dunnocks favor habitats that include forests, woodlands, shrubs, gardens, parks, and hedgerows.
Dunnocks are active during the day typically feeding on the ground. They are usually seen alone, but sometimes, may join foraging flocks. Dunnocks are territorial especially during the breeding season and may engage in conflict with other birds that encroach upon their nests. Males sometimes share a territory and exhibit a strict dominance hierarchy; older birds tend to be the dominant males and first-year birds are usually sub-dominant. Female territorial ranges are almost always exclusive. However, sometimes, multiple males may co-operate to defend a single territory containing multiple females. The main call of dunnocks is a shrill, persistent 'tseep' along with a high trilling note, which betrays the bird's otherwise inconspicuous presence. The song is rapid, thin, and tinkling, a sweet warble which can be confused with that of the Eurasian wren, but is shorter and weaker.
Dunnocks have variable mating systems. Females are often polyandrous, breeding with two or more males at once, which is quite rare among birds. Other mating systems also exist, depending on the ratio of male to females and the overlap of territories. When only one female and one male territory overlap, birds will form monogamous pairs. Sometimes, two or three adjacent female territories overlap one male territory, and so polygyny is favored, with the male monopolizing several females. Polygynandry also exists, in which two males jointly defend a territory containing several females. Polyandry, though, is the most common mating system of dunnocks found in nature. Dunnocks typically breed between March and July, however, in Russia, their breeding season occurs from May to August. These birds prefer to build their nests low in a bush or conifer. The nest is made from twigs and moss and lined with soft materials such as wool or feathers. The female lays 3 to 5 unspotted blue eggs and incubates them for about 12-13 days. The chicks hatch partially covered with blackish down and remain in the nest for about 12 days. Broods, depending on the population, can be raised by a lone female, multiple females with the part-time help of a male, multiple females with full-time help by a male, or by multiple females and multiple males. In pairs, the male and the female usually invest parental care at similar rates.
There are no major threats to the dunnock at present.
According to the IUCN Red List, the total population size of the dunnock is 25,000,000-43,999,999 mature individuals. In Europe, the breeding population consists of 12,700,000-21,800,000 pairs, which equates to 25,400,000-43,500,000 mature individuals. Currently, this species is classified as Least Concern (LC) on the IUCN Red List but its numbers today are decreasing.