Prioksko-Terrasny Nature Reserve covering 4945 ha, 134 species of birds from 14 orders (Ciconiiformes, Anseriformes, Falconiformes, Galliformes, Gruiformes, Charadriiformes, Columbiformes, Cuculiformes, Strigiformes, Caprimulgiformes, Apodiformes, Coraciiformes, Piciformes, Passeriformes) had been registered by 1991. Later 5 more species were observed here. Thus, by the present time, the list of species of birds registered in the Reserve numbers 139 species. About 55% from them are Passerines. Most of birds of the Reserve belong to migratory breeding species or to nomadic breeding species. Some species are vagrants in the Reserve and in the Moscow Region (nutcracker Nicifraga caryocatactes (L.), etc.). Birds, nesting in central parts of Russia
Evolution of birds debate. There is significant evidence that birds emerged within theropod dinosaurs, specifically, that birds are members of Maniraptora, a group of theropods which includes dromaeosaurs and oviraptorids, among others. As more non-avian theropods that are closely related to birds are discovered, the formerly clear distinction between non-birds and birds becomes less so. This was noted already in the 19th century, with Thomas Huxley writing: We have had to stretch the definition of the class of birds so as to include birds with teeth and birds with paw-like fore limbs and long tails. There is no evidence that "Compsognathus" possessed feathers;