Wild Barcelona: Montjuïc frogs

A roar of outraged indignation would drift across Montjuïc and you’d know the referee had got it wrong once again. That was when Espanyol football club used to play in the Olympic Stadium, when on spring evenings the sound of their supporters would merge with the frog choruses mounting in equally impressive crescendos from the nearby Jardins de Verdaguer.

The Espanyolistas have moved on, but their amphibian competitors in decibel levels remain in full-throated swing. You can discern two distinct songs: the laughter-like reverberations of the Iberian water frog, and the raucous, startlingly loud call produced by the diminutive Mediterranean tree frog.

The park is on the site of an old quarry and its steep slopes have been landscaped into a series of square terraced ponds, the focus of amphibian activity. By August, the long, wild nights of frog singing have calmed down, but their fruits are much in evidence, as quantities of froglets emerge.

A splash and some bubbles are often the only signs of the water frogs, who’ll dive under the lily pads as you approach. The grass-green tree frogs, however, trust in camouflage, and a careful scrutiny of the pond vegetation will usually reveal them, attached securely to leaves, legs neatly tucked in.

Not as aquatic as the water frogs, their toes are less webbed and strong suction pads allow them to climb up and away from the ponds. In fact you can spot them all over the park once the breeding season’s over: in the ornamental flower beds, the middle of bushes, and even on leaves sticking right out of the park’s railings, by the funicular station.

Tree frogs are smoothly textured, and quite uniformly coloured, with a black stripe falling mask-like across their eyes. And very rarely—reportedly one in 25,000—a vivid blue morph crops up, like a vision from the Amazonian rainforest.