The rock faces are the habitat of a large number of plants and animals with specific living conditions (rupestrian or rupicolous species), including many rare or endangered species. Many birds in particular have chosen this environment as their nesting place: both the overhangs and the dense barrier of vegetation on the slopes make the rock walls inaccessible and therefore safe from the disturbance of man and that of many predators (foxes, badgers, weasels, martens, etc.).
The rocky walls of Monte Caslano are also inhabited by a large number of birds, some of which, however, only during their breeding season, while others only in autumn and winter. The largest nesting birds include the common raven and some birds of prey such as the peregrine falcon, buzzard and brown kite. The latter two species take advantage of the wooded ledges of the mountain to build their nests. Although not nesting on the walls of the mountain, even the honey buzzard, sparrow hawk and kestrel can be observed in flight over the mountain during certain periods of the year. Another characteristic species is the nightjar, a medium-sized nocturnal bird that frequents the dry and semi-forested meadows of the steep, south-facing terrain. Among the smaller rupestrian birds there are instead the Alpine swift, the Eurasian crag martin, the black redstart, the solitary blue rock thrush and the wallcreeper. The latter two species have so far been observed only outside the nesting period.
In recent years, the rock faces have been subjected to increased human pressure due in particular to sports rock-climbing. This discipline can in fact compromise the nesting of some priority species for conservation in Ticino and Switzerland, such as the peregrine falcon, the eagle owl, the blue rock thrush and the wallcreeper. In order to guarantee their conservation, it is therefore necessary to protect the nesting places during the breeding period, regulating the use of certain rock walls.
