Birds (In Latin avis = birds) are vertebrates covered with feathers, with forelimbs turned into wings, and hindlimbs used for bipedal locomotion (two feet). In their evolutionary path, birds acquired several characteristics that allowed them to fly, such as the presence of feathered wings, large muscles to flap their wings and reduced animal weight, such as the acquisition of pneumatic bones (hollow, light, delicate) and filled with air bags). In addition, feathers also help with thermal regulation, acting as an insulator and preventing birds from losing heat to the environment. We can also mention the loss or fusion of several bones and organs (the urinary bladder, for example, is absent in this group). Although the characteristics of modern birds are mainly related to flight, there are exceptions, such as birds that do not have wings, those that have reduced wings and those that use their wings to swim, such as penguins. Currently, there are about 10,000 species of birds distributed around the world. In Brazil, about 1,800 species are known and, in the state of São Paulo, about 700 species.
In the areas of Usina São Francisco, 205 species were observed, belonging to 16 orders and 51 families.
SENSES
A flying animal must have great visual acuity, so vision is an important sense for birds, and some call attention to their acute vision, especially predatory birds (prey) such as owls and eagles, which need to locate prey of movements fast, quickly and accurately, usually over great distances. Some have excellent hearing, such as owls. At the same time, vocalization (singing) has also become more elaborate, allowing communication between species. The sense of smell is well developed, especially for those who feed on carrion and for those who use it to find fish, nests and even partners.
HABITAT HABITS AND USE
Birds are the only animals that have colonized all regions of the Earth, aided by their ability to fly and endothermia (warm blood). Few animals have adapted to life in the polar and desert regions, but many species of birds have done so (such as snow owls, hawks and penguins).: 35-45.
FOOD
The eating habits of birds have evolved to adapt to the incredible diversity of environments. They eat everything: from tiny insects to mammals and fish. In addition, some species, such as vultures, basically feed on carcasses of large dead animals. Because of this varied diet, birds have developed many physical adaptations that help them hunt for their favorite food. Their beaks, in particular, vary widely in shape, size and strength, depending on their diet. According to their beaks and diets, we can classify them as granivores, frugivores, omnivores, insectivores, filters and carnivores.
REPRODUCTION
The vast majority of birds are monogamous, forming breeding pairs. They are oviparous and generally build nests with a great diversity of shapes and materials. When the eggs are laid in the nest, they are hatched by one or both parents, who sit on the eggs to keep them at the appropriate temperature for their development.
DEFENSE
Birds have several types of structures that can be used for this purpose, such as strong and pointed beaks, claws and spurs on the wings. They also exhibit behaviors, such as vocalizations or adopting postures, to appear larger or to protect their young and nests.
CONSERVATION
Birds perform well-defined and very important ecological functions, regulating the population dynamics of various groups of invertebrates and vertebrates, such as snakes and rodents, preventing overpopulation of these species and, consequently, ecological imbalance. In addition, necrophagous birds (that eat carrion) do a useful job in nature, removing animal remains in a state of putrefaction and assist in pollination and seed dispersal. Birds, like hummingbirds, pollinate many species of flowers. There are also birds that are important in the economic sector, such as chickens, turkeys, etc., that have been used for millennia in human nutrition. Some also provide fertilizer from their excrement and act as biological indicators, since the occurrence of deforestation, burning, pollution of rivers, lakes, etc., affect them. The disappearance or increase of some bird populations are indicators of changes in environmental quality.
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