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. Distribution and habitat Dunnocks are native to large areas of Eurasia, inhabiting much of Europe including Lebanon, northern Iran, and the Caucasus. They are the only commonly found accentor in lowland areas; all the others inhabit upland areas. Dunnocks were successfully introduced into New Zealand during the 19th century, and are now widely distributed around the country and some offshore islands. Favoured habitats include woodlands, shrubs, gardens, and hedgerows where they typically feed on the ground, often seeking out detritivores as food. Territoriality Dunnocks are territorial and may engage in conflict with other birds that encroach upon their nests. Males sometimes share a territory and exhibit a strict dominance hierarchy. Nevertheless, this social dominance is not translated into benefits to the alpha male in terms of reproduction, since paternity is usually equally shared between males of the group. Furthermore, members of a group are rarely related, and so competition can result. Female territorial ranges are almost always exclusive. However, sometimes, multiple males will co-operate to defend a single territory containing multiple females. Males exhibit a strong dominance hierarchy within groups: older birds tend to be the dominant males and first-year birds are usually sub-dominant. Studies have found that close male relatives almost never share a territory. The male's ability to access females generally depends on female range size, which is affected by the distribution of food. When resources are distributed in dense patches, female ranges tend to be small and easy for males to monopolise. Subsequent mating systems, as discussed below, reflect high reproductive success for males and relatively lower success for females. In times of scarcity, female territories expand to accommodate the lack of resources, causing males to have a more difficult time monopolising females. Hence, females gain a reproductive advantage over males in this case. Breeding Mating systems The dunnock possesses variable mating systems. Females are often polyandrous, breeding with two or more males at once, which is quite rare among birds. This multiple mating system leads to the development of sperm competition amongst the male suitors. DNA fingerprinting has shown that chicks within a brood often have different fathers, depending on the success of the males at monopolising the female. Males try