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,
Preening (bird) preening. The conflict between two incompatible drives, such as incubating and escape, can also lead a bird to engage in displacement activities. Nesting Sandwich and common terns preen when they have been alarmed by a potential predator or when they have had an aggressive encounter with a neighboring bird, for instance. Fighting European starlings will break off their battles to preen. Although preening is primarily an individual behaviour, some species indulge in allopreening, with one individual preening another. It is not particularly common among birds, though species from at least 43 families are known to engage in the mutual activity.