It is a warning that the brain is not getting enough blood â and one in four people who have a mini stroke go on to have a full-blown stroke, often within 72 hours. In a mini stroke, a blood clot passes through the brain, meaning symptoms are temporary.
Birds (Aves), a subgroup of reptiles, are the last living examples of dinosaurs. They are a group of endothermic vertebrates, characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweight skeleton. Birds live worldwide and range in size from the 5 cm (2 in) bee hummingbird to the 2.70m (9 ft) ostrich. They rank as the class of tetrapods with the most living species, at approximately ten thousand, with more than half of these being passerines, sometimes known as perching birds. Birds are the closest living relatives of Crocodilia.
Birds are vertebrates with feathers, modified for flight and for active metabolism. Birds are a monophyletic lineage, evolved once from a common ancestor, and all birds are related through that common origin.