Wild Barcelona: Crossing paths in Collserola

Dense with broom, brambles and lianas, off-trail Collserola Park can be thorny and impenetrable.

The inaccessible gullies and long overgrown terraces explain why so much wildlife survives in this unique metropolitan natural park, which receives two million visitors a year. But all manner of wild encounters can be experienced without straying off the paths.

Sometimes the sightings are brief: thick coils of the magnificent Montpellier snake, tempted out for a sunbathe, are already rapidly withdrawing from view as you round the corner. But a tiny juvenile southern smooth snake, desperately trying to reach cover, can be snatched up for closer examination.

The scuttle of wall lizards is a constant as you walk and occasionally you come across a slow worm with its beautiful bronze sheen. Legless, it swims through the dust to safety, its rippling movement convincing many they’re in the presence of a snake. As with any lizard, handling is not advisable, since you can be left just holding the tail.

Exposed in the open, many creatures are startlingly visible. Exotic-looking caterpillars, inching slowly along, have to be helped on their way, out of reach of passing wheels. A monochrome cream-spot tiger moth, which conceals flaming orange hindwings, lay starkly on the ground and when approached, flew onto the oncoming boot.

On twilight walks, a torch is useful. A nightjar fledgling, crouched still on the track, was spotted by the reflective gleam in its eyes. The parents circled, two anxious shadows, until their offspring flew silently away. The light also revealed a fox, on the move in the summer dusk, who paused at the crossroads and turned to stare coolly at the passers-by.

And at any time of year, day or night, a boar might break cover and thunder across the track, snorting as it goes. You’re left watching the dust as it settles, trying to recover interrupted thoughts.

Lucy Brzoska runs nature tours and writes for www.iberianature.com