Dunnock 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,
Acrocephalus (bird) Acrocephalus (bird) The Acrocephalus warblers are small, insectivorous passerine birds belonging to the genus "Acrocephalus". Formerly in the paraphyletic Old World warbler assemblage, they are now separated as the namesake of the marsh and tree warbler family Acrocephalidae. They are sometimes called marsh warblers or reed warblers, but this invites confusion with marsh warbler and reed warbler proper, especially in North America, where it is common to use lower case for bird species. These are rather drab brownish warblers usually associated with marshes or other wetlands. Some are streaked, others plain. Many species breeding in temperate regions are migratory. This