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
Common crane Waterbirds" (AEWA) applies. In Ireland, despite being extinct for over 200 years, the common crane plays a very important part in Irish culture and folklore and so thus recent efforts to encourage it back to Ireland are received with much enthusiasm. The Kranich Museum in Hessenburg, Mecklenburg-Vorpommern, Germany, is dedicated to art and folklore related to the common crane. The common crane is the sacred bird of the god Hephaestus, and it features heavily in the god's iconography. Common crane The common crane ("Grus grus"), also known as the Eurasian crane, is a bird of the family Gruidae, the cranes.