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 ostrich is scarce in dry and hot environment, and this poses a challenge to the ostrich's water consumption. Also the ostrich is a ground bird and cannot fly to find water sources, which poses a further challenge. Because of their size, common ostriches cannot easily escape the heat of their environment; however, they dehydrate less than their small bird counterparts because of their small surface area to volume ratio. Hot, arid habitats pose osmotic stress, such as dehydration, which triggers the common ostrich’s homeostatic response to osmoregulate. The common ostrich is well adapted to hot, arid environments through specialization of excretory