Dunnock system can be shifted from one that favours female success (polyandry), to one that promotes male success (monogamy, polygynandry, or polygyny). The dunnock builds a neat nest (predominantly from twigs and moss and lined with soft materials such as wool or feathers), low in a bush or conifer, where adults typically lay three to five unspotted blue eggs. Broods, depending on the population, can be raised by a lone female, multiple females with the part-time help of a male, multiple females with full-time help by a male, or by multiple females and multiple males. In pairs, the male and the
Common raven Common raven The common raven ("Corvus corax"), also known as the northern raven, is a large all-black passerine bird. Found across the Northern Hemisphere, it is the most widely distributed of all corvids. There are at least eight subspecies with little variation in appearance, although recent research has demonstrated significant genetic differences among populations from various regions. It is one of the two largest corvids, alongside the thick-billed raven, and is possibly the heaviest passerine bird; at maturity, the common raven averages in length and in mass. Common ravens can live up to 21 years in the wild, a lifespan