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,
Common sandpiper Common sandpiper The common sandpiper ("Actitis hypoleucos") is a small Palearctic wader. This bird and its American sister species, the spotted sandpiper ("A. macularia"), make up the genus "Actitis". They are parapatric and replace each other geographically; stray birds of either species may settle down with breeders of the other and hybridize. Hybridization has also been reported between the common sandpiper and the green sandpiper, a basal species of the closely related shank genus "Tringa". The common sandpiper was one of the many bird species originally described by Linnaeus in the landmark 1758 10th edition of his "Systema Naturae", where