Water and drinking
Many birds require water, even though their excretory system and lack of sweat glands lessen the physiological demands. Certain arid birds can get all the water they require from the moisture in their food. Other adaptations made by some include panting, letting their body temperature rise, and reducing moisture loss through evaporative cooling. [162] Seabirds have salt glands inside their heads that filter excess salt from their nostrils, and they can also consume seawater. [163].
Most birds raise their heads to allow water to run down their throats after scooping it into their beaks. Certain species, particularly those found in arid regions, such as button-quail, bustards, finches, pigeons, and mousebirds, have the ability to absorb water without having to tilt their heads back. [164] Certain desert birds rely on water sources, and sandgrouse are well recognized for gathering regularly at waterholes. Many plovers and nest-building sandgrouse wet their belly feathers to deliver water to their young. [165] Some birds regurgitate water along with food or carry it in their crops for the chicks at the nest. The pigeon family, flamingos, and penguins have evolved to create crop milk, a nutritious fluid that they feed to their young. [166].
Feather careMain article:
Because they are essential to a bird’s survival, feathers need to be maintained. Feathers are susceptible to fungal infections, ectoparasitic feather mites, and bird lice in addition to normal wear and tear. [167] Frequent preening with the application of preen gland secretions maintains the feathers’ physical condition. Birds also bathe in water or dust themselves. While some birds dive into shallow water, more avian species may do so, and arboreal species frequently utilize precipitation or dew that collects on leaves. In dry areas, birds use the loose dirt as a dust bath. It’s also believed that the behavior known as “anting,” in which the bird invites ants to fly through its feathers, aids in lowering the ectoparasite load in its feathers. Numerous species extend their wings and expose them to direct sunlight, which is also believed to aid in lowering the activity of fungi and ectoparasitic insects that could harm feathers. [168][169].
Resting and roosting”Roosting” redirects here. For other uses, see
Birds’ high metabolic rates during the day’s active hours are complemented by rest periods. Vigilant sleep is a type of sleep that sleeping birds frequently employ. It consists of rest intervals punctuated by brief “peeks” that open their eyes, making them sensitive to disturbances and enabling them to quickly flee from danger. [200] It is thought that swifts can slumber while in the air, and radar data indicates that when they are roosting, they align themselves to face the wind. [201] There have been rumors that some types of sleep could be achievable while flying. [202].
Additionally, certain birds have shown that they can induce slow-wave sleep by focusing on one side of their brain at a time. The birds typically use this ability based on where they are in relation to the flock’s outside. By observing the flock’s outer edges, the eye across from the sleeping hemisphere might be able to stay alert for predators. This adaptation is also known from marine mammals. [203] Because communal roosting reduces body heat loss and predator-related risks, it is a common practice. [204] Safety and thermoregulation are major considerations when selecting nesting locations. [205] Large herbivores on the African savanna that oxpeckers use are examples of unusual mobile roost sites. [206].
While some birds nestle their beaks among their breast feathers, many slumbering birds bend their heads over their backs and tuck their bills in their back feathers. Many birds perch on one leg, but in particularly chilly climates, some may tuck their legs up into their feathers. Birds that perch have a mechanism called tendon-locking that helps them stay attached to their perch while they sleep. Many ground birds roost in trees, including pheasants and quails. A few Loriculus parrots with their roost hanging upside down [207] Some hummingbirds experience a nocturnal torpor that is accompanied by a decrease in their metabolic rates. [208] Almost a hundred other species, such as woodswallows, nightjars, and owlet-nightjars, exhibit this physiological adaptation. A particular species, the common poorwill, even goes into hibernation. [209] Since they lack sweat glands, birds can lose water through their skin and can cool themselves by standing in water, moving to the shade, panting, fluttering their throats, increasing their surface area, or employing specialized behaviors like urohidrosis. [210][211].
FAQ
Why are birds vertebrate?
What are the 5 vertebrates and 5 invertebrates?
Do birds have backbone?
Are there any invertebrate mammals?