The diverse environments and the limited presence of man make the Giogo-Casaglia area particularly suited to numerous animal species.
After a period that witnessed a decrease in the presence of the species, which started in the 70s, the wolf (Canis lupus) again occupies the territory that had been taken away from it. This is due to certain facts: a law that has listed it among the many protected species; an increase in wild hoofed animals; and the relocation of man from mountainous areas to the city.
The wolf feeds almost exclusively on wild animals. It is difficult to sight a wolf, whose extremely developed senses help him avoid human contact. Along the trails, however, there are numerous traces of his presence: excrement, with traces of skin and bone, from 15-30 cm in length and 2-3 cm in diameter; and paw prints, larger than those of large dogs, and elongated. The ecological distribution of the species in the area has been under study since 1993, with the collaboration of various research institutes.
Birds of prey
Along the trails that tether the Giogo-Casaglia complex, we can sight numerous birds of prey. Among the birds that occupy the daytime sky we can sight the Golden Eagle (Aquila chrysaetos), a couple of which reside permanently in the Rovigo valley area; and the Peregrine falcon (Falco preregrinus), a species with pointed wings and tail feathers, which is considered vulnerable and included in the UCN (Unione Mondiale per la Conservazione della Natura) Red List. The kestrel (Falco tinnunculus), a small falcon with long pointed wings, the buzzard (Buteo buteo), the sparrowhawk (Accipiter nisus), the goshawk (Accipter gentilis), the honey-buzzard (Pernis apivorus) and the Harrier eagle (Circaetus gallicus) can also be sighted in the area.
At night, the woods are populated with numerous birds of prey: the most common is the owl (Stryx aluco).
Wild hoofed animals
Numerous attempts to introduce and re-introduce wild hoofed animals in the Apennines has had positive effects. It is not uncommon today to hear the call of the roebuck (Capreolus capreolus) in summer. We can also find numerous deer prints (Dama dama), animals which are not native to the land, but which were introduced and can be sighted in groups in open areas at dawn. The buck (Cervus elaphus) is less present and fewer in number. There are numerous traces of the wild boar (Sus scrofa), which are abundant in the area.
Amphibians and reptiles
In the streams and ponds in the Giogo-Casaglia area, we find numerous different types of frogs, newts and salamanders, as well as the uncommon spectacled salamander (Salamandrina tergiditata), and the rare Apennine yellow bellied toad (Bombina pachypus), a small toad with a yellow spotted belly, the Alpine newt, the crested newt and the Speleomantis. Other species that can be sighted are the Green whip snake (Hierophis viridiflavus), a green and black snake also called “frustone”, whip, because it unravels like a whip and slips into the rivers and streams, and the common grass snake (Natrix natrix). Vipers (Vipera aspis) are more difficult to find.
In the Giogo-Casaglia complex we find many types of birds: jay birds (Garrulus glandarius), titmice, chaffinches and robin redbreasts. There are different types of woodpeckers: the green woodpecker (Picus viridis), classified in the Tuscan Red List of endangered species as 'least concern' (lowest risk), the Great spotted woodpecker (Picoides major) and the Lesser spotted woodpecker (Picoides minor), classified in the Tuscan Red List of endagered species as 'average vulnerable', and whose preferred habitat is chestnut forests. The streams host the rare White throated dipper (Cinclus cinclus), an aquatic bird specialized in underwater immersions in the cold mountain rivers where it searches for insects.
Along the Giogo-Casaglia trails, we can find traces of other animals, for example: the fox, the badger, the stone marten, the weasel and the porcupine. In the waters of the Rovigo River, we find fresh-water crayfish (Austropotamobius pallipes), lower in number because of the alterations in the springs and rivers, and because of illegal fishing; the crayfish is a bioindicator and can live only in clean waters. It is a protected species by law and considered today vulnerable under IUCN Red List classification.
From spring to autumn there are an impressive number of butterflies, some of which interest the European community and are a protected species under Habitat classification. They are: the Lycaena arion (Maculinea arion) and the Jersey tiger (Callimorpha quadripunctata).
For some years now, thanks to the use of camera trap sets we have been able to document the presence of the wildcat (Felis silvestris) in the area.