Birds

This section presents the birds (Aves L. 1758), this class of endotermis vertebrates cladistically referable as origin to a branch of the theropod dinosaurs characterized by the presence of toothless beaks and forcules, bodies covered with plumage and stuffed with aerated bags, anterior fingers fused, hard shelled eggs, high metabolism and hollow yet robust bones.
Birds have an ecological role that can not be overlooked. From insect control, to the role of pollinators in the large forests of the equatorial countries to that of seed transport.
Another non-secondary role of birds in the economy of the planet is to bring back on the mainland some of the nutrients for the plants – phosphates and nitrogen compounds – that have reached the water.
According to different classification criteria, the number of known bird species ranges between 9,000 and 10,500, of which at least 120 have become extinct in historical times.

Guido Bissanti