Birds Birds first appeared possibly from a lineage of biped dinosaurs that developed feathers. All bird species reproduce through the amniotic egg and, with extremely rare exceptions, show parental care of the offspring. Unlike previous vertebrates, birds are endothermic, which means they are capable of maintaining a stable body temperature. In Portugal there are about 400 bird species and in the Alentejo a significant part of this avian diversity can be found, some species being unique to the habitats typical of this area. It is worth noting the presence of endangered species such as the great bustard, the black vulture and the European roller. Birds are the most abundant and easiest to observe vertebrates of the Neves-Corvo region as they are mostly diurnal. They are also the most diverse group, reflecting the large variety of ecological niches they exploit and their ability to colonise widely due to the mobility that comes with flight as a behaviour characteristic. The main threats to birds are the loss and fragmentation of native vegetation, road accidents, collision with electric wires and fences, global climatic changes, hunting and, in the case of carnivorous and scavenger species, both accidental and intentional poisoning through consumption of prey and carcasses.