Close encounters in Collserola

Written by Lucy Brzoska

While out walking on a warm evening at the beginning of September, it was Nick who first spotted this tiny snake on the track, rippling as fast as it could, anxious to reach cover on the other side. Once caught, it remained still, except for the flickering of its tongue. We weren’t sure of its identity, so it paid to have the camera at hand. The photograph clearly shows a black coronet and an elusive blue shimmer: the marks of the non-venomous Southern smooth snake (Coronella girondica).

We were lucky to stumble on it, as they’re not common in Collserola. Shy and secretive night hunters, they search out geckos, skinks and grasshoppers and kill by constriction. A passing resemblance to the viper is thought to work as a defence. We found the snake in the more open southern part of Collserola, an area of grass, shrubs and scattered trees, a summer hunting ground for Short toed eagles.

At the opposite end of the park, not far from a spring, this dragonfly was captured clinging to a bush. I’d have described it as red, till I got home and saw its range of fairground colours: a horse from a devil’s carousel. The rows of spikes on the legs are impressive, ensuring a firm grip on prey. The dimensions of its eyes immediately suggest extraordinary powers of vision.

When identifying the dragonfly, the yellow stripe along the length of the legs pointed me to the Common darter (Sympetrum striolatum), which was confirmed when Sue put her shots up on the forum.

Finally, in the centre of Collserola, the most disturbed and built-up part, this creature was rescued from a busy track. A convoy of cars was driving away from a restaurant, coating us and everything around in dust. The Eyed hawk moth caterpillar (Smerinthus ocellata) was carried to a safer place on a notebook, hence the garish studio background for its portrait.

The caterpillar has a distinguishing blue horn, slanting white stripes (7 in all) and red spiracles (breathing holes).