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,
Bird colony (Enantiornithes), in sediments from the Late Cretaceous (Maastrichtian) of Romania. Approximately 13% of all bird species nest colonially. Nesting colonies are very common among seabirds on cliffs and islands. Nearly 95% of seabirds are colonial, leading to the usage, seabird colony, sometimes called a rookery. Many species of terns nest in colonies on the ground. Herons, egrets, storks, and other large waterfowl also nest communally in what are called heronries. Colony nesting may be an evolutionary response to a shortage of safe nesting sites and abundance or unpredictable food sources which are far away from the nest sites. Colony-nesting birds