Dunnock relatively lower success for females. In times of scarcity, female territories expand to accommodate the lack of resources, causing males to have a more difficult time monopolizing females. Hence, females gain a reproductive advantage over males in this case. The dunnock possesses variable mating systems. Females are often polyandrous, breeding with two or more males at once, which is quite rare among birds. This multiple mating system leads to the development of sperm competition amongst the male suitors. DNA fingerprinting has shown that chicks within a brood often have different fathers, depending on the success of the males at monopolising
European Bird Census Council Census News", which has been running since 1987. European Bird Census Council The European Bird Census Council (EBCC) is an ornithological organisation which studies the population, distribution and demographics of European birds in order to inform conservation and management efforts. The organisation is headquartered in the Netherlands, and has active members in over 40 countries. The EBCC was founded in 1992, following the merger of two ornithological organisations, the European Ornithological Atlas Committee and the International Bird Census Committee. The EBCC is responsible for the Pan-European Common Bird Monitoring Scheme (PECBMS), which aims to collect data from national bird monitoring