Prunella modularis Linnaeus, 1758 ♂
Common names: Dunnock [En], Accenteur mouchet [Fr], Heggenmus [Nl], Heckenbraunelle [De], Passera scopaiola europea [It], Acentor Común [Es], Θαμνοψάλτης, Θαμνοψάλτης, Κελαηδόστρουθος [Gr], Çıt Serçesi, Dağ Bülbülü [Tu]
Tubize, BRABANT ● Belgium
Description: A European robin-sized bird, the dunnock typically measures 13.5–14 cm in length. It possesses a streaked back, somewhat resembling a small house sparrow. Like that species, the dunnock has a drab appearance in order to avoid predation. It is brownish underneath, and has a fine pointed bill. Adults have a grey head, and both sexes are similarly coloured.
Biology: Studies have illustrated the fluidity of dunnock 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 to ensure their paternity by pecking at the cloaca of the female to stimulate ejection of rival males' sperm. Dunnocks take just one-tenth of a second to copulate and can mate more than 100 times a day. Males provide parental care in proportion to their mating success, so two males and a female can commonly be seen provisioning nestlings at one nest.
Other mating systems also exist within dunnock populations, depending on the ratio of male to females and the overlap of territories. When only one female and one male territory overlap, monogamy is preferred. Sometimes, two or three adjacent female territories overlap one male territory, and so polygyny is favored, with the male monopolising several females. Polygynandry also exists, in which two males jointly defend a territory containing several females.
When given food in abundance, female territory size is reduced drastically. Consequently, males can more easily monopolise the females. Thus, the mating system can be shifted from one that favours female success (polyandry), to one that promotes male success (monogamy, polygynandry, or polygyny).
The dunnock builds a neat nest (predominantly from twigs and moss and lined with soft materials such as wool or feathers), low in a bush or conifer, where adults typically lay three to five unspotted blue eggs.
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 invest parental care at similar rates. However, in trios, the female and alpha male invest more care in chicks than does the beta male. In territories in which females are able to escape from males, both the alpha and beta males share provisioning equally. This last system represents the best case scenario for females, as it helps to ensure maximal care and the success of the young.
Habitat: Favourite habitats include woodlands, shrubs, gardens, and hedgerows.
Distribution: Much of Europe including Lebanon, northern Iran, and the Caucasus. Dunnocks were successfully introduced into New Zealand during the 19th century, and are now widely distributed around the country and some offshore islands.