Dunnock 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. Polyandry, though, is the most common mating system of dunnocks found in nature. Depending on the population, males generally have the best reproductive success in polygynous populations, while females have the advantage during polyandry. Studies have illustrated the fluidity of dunnock mating systems. When given food in abundance, female territory size is reduced drastically. Consequently, males can more easily monopolise the females. Thus, the mating
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