There are no natural rocky environments in the Park, except for the small “enclave” of Escletxes del Papiol. Nonetheless, a very specific type of fauna takes advantage of some of the Serra’s abandoned quarries, like that of Can Farrés in Santa Creu d’Olorda, or the small, old quarry near Sant Just Desvern.

The species that can be seen in these spots are the blue rock thrush (Monticola solitarius), common raven (Corvus corax), common kestrel (Falco tinnunculus), black redstart (Phoenicurus ochruros) and even the Eurasian eagle-owl (Bubo bubo), which has suffered the effects of poaching. There have also been sightings more recently of the peregrine falcon (Falco peregrinus), a visitor to these parts and now a serious contender to enhance the list of birds that nest in the Park.

In Collserola these species can only be found in these types of locations, which are ideal for their nesting. Leaving aside for a moment the undoubted impact that quarrying activities have had in the Park, we should highlight the capability that many species possess to colonise new habitats and enrich the biodiversity of the Serra, and we should, once again, congratulate ourselves for enabling this to happen.