Articles in ‘amphibians’

Blue in the shade

Written by Lucy Brzoska

By a riera in Montseny, Southern white admirals were flying, flickering past in black and white.  One settled in the shade, among nettles and brambles, and at this angle it turned deep blue, a colour it usually conceals.

southern white admiral (Limenitis reducta) turning blue

Overlooking the stream, there were glints of metallic turquoise as Beautiful demoiselles displayed.

beautiful demoiselle (Calopteryx virgo) in Montseny wings closedbeautiful demoiselle (Calopteryx virgo) on Montseny displaying

After a summer shower, rain drops and tiny tree frogs clustered on the waxy leaves of Montjuïc’s pond vegetation. One day I’ll find the elusive blue morph.

mediterranean tree frog on Montjuic after the rain

Urban ravens

10553405_724644314276096_1549117052573987740_n Strongly associated with wilderness, when ravens turned up in the intensely urban environment of Barcelona this summer, it caused surprise and excitement. Two young ravens, still weak flyers, were rescued off the street, and set free after a couple of weeks in a wildlife recuperation centre. Regular observations of ravens have been made in the area of Park Ciutadella throughout the summer. By coincidence, ravens have also made an appearance in Manhattan this year. More photos and information from Galanthus.

Viperine snake takes on large Water frog (and gives up)

Written by Lucy Brzoska

Walking along a hot, dusty track in the Alt Emporda, a woodchat shrike singing in a nearby tree and bee eaters dipping and diving over the olive groves, we heard a piteous crying sound.   It was coming from the long trough-like irrigation channel at the side of the track: a strongly protesting Iberian water frog (Pelophylax perezi) was in the grip of a Viperine snake (Natrix maura).

viperine  snake (Natrix maura) captures Iberian water frog

The aquatic snake had seized the frog by the leg and was swimming vigorously up and down the channel, the belly of its helpless prisoner flashing white in all the whirling.

viperine snake swims with captive water frog

The non-venomous snake next tried tightly knotting itself around its resistant prey, its mouth still gripping the leg.

viperine snake knots itself around iberian water frog

Suddenly it seemed to tire, released its coils and swam to the side of the channel.  The frog waited a moment, and then tried to swim away.  But its movement immediately triggered a reaction in the snake, which this time seized the amphibian by the back.

viperine snake (Natrix maura) biting iberian water frog (Pelophylax perezi)

Despite the considerable gape of the Viperine, it was clear the frog was too big for it to swallow. Eventually the frog was allowed to make a getaway, but fatally weakened, it didn’t survive the attack.

Zooming in on Montjuic (vi): autumn

Written by Lucy Brzoska

An old olive tree is creaking.  It’s not the wind, but the sound of a tree frog singing from somewhere inside the hollow trunk.  The warm humid October weather suits Mediterranean tree frogs, and they appear on the dew-saturated leaves, in bushes and flower beds.  Some had shimmied up the newly blooming Red hot pokers.

Migrating song thrushes have settled unobtrusively on the hill. You’re aware of them but they hide out of sight, communicating with low calls.  Other arrivals are chiffchaffs.  They’re far less shy, too small to fear the shotgun.

I’m going along the cobbled path to the Sot del Migdia, and feel watched.  Just above me, I see tall ears, and a prominent brown eye.  It’s a boom year for rabbits on Montjuic – newly excavated warrens are gaping. They’ll be glad summer’s over, and the arid slopes have turned green, not so much from rain, which has been scarce, but from the heavy dew.

Iberian Blue-tailed Damselflies on Montjuic

Written by Lucy Brzoska

Large flocks of Blue-tailed damselflies (Ischnura graellsii) emerge from the ponds in Montjuic’s Jardins de Verdaguer.  They’re so tiny that in flight often all you can make out is a quivering blue blob.  When they settle, the spot of blue turns out to be the tail end of an endless abdomen (segment 8, to be precise).

the-tiny-iberian-blue-tailed-damselfly-ischnura-graellsii

Throughout the month of June the Blue-tails are harvested by House sparrows.  Bills bristling with wings,  the sparrows somehow manage to keep on collecting without dropping any of the existing catch.  You can imagine their nestlings getting fat on plentiful damselfly protein.

house-sparrow-hunts-for-damselflies-in-the-pond

By the end of July, the pond vegetation is full of Tree frogs (Hyla meridionalis),  perching motionless alongside the Blue-tails.  I found one very slowly ingesting its meal, till it seemed to be champing on a blue-tipped cigar.  One tremendous gulp and the rest was engulfed.

tree-frog-hyla-meridionalis-eats-bluetailed-damselfly-ischnura-graellsii

Food chains are long and complex.  Damselflies hunt small flies . . .

cannibalism-in-blue-tailed-damselfies-female-eats-teneral

. . . and each other.  As the sunlight broke free of the early morning clouds, it stirred the damsels from their resting places. A newly emerged Blue-tail on its maiden flight was immediately snatched, hoisted up and devoured by a mature female.

Tree Frogs in Barcelona

Written by Lucy Brzoska

Montjuic, fragmented into a hundred spaces, often comes up with the unexpected.  One of its disused quarries was landscaped into a steeply sloping garden, with carefully tended ornamental flower beds and terraced brick ponds.  Layered with water lilies, these harbour an apparently vast number of Iberian Water frogs (Rana perezi or Pelophylax perezi)), whose massed choruses used to compete with the roar of Espanyol fans when their team still played in the Olympic stadium.

One of the ponds is thick with ribbon-like rushes, and a tall aquatic  plant with large flat leaves.  On one of these I noticed a small green blob, about half the size of my thumb nail, and realised there was a colony of Tree Frogs here too.

young-tree-frog-hyla-meridionalis

The species found in Catalunya is Hyla meridionalis, the Stripeless Mediterranean Tree Frog, but the pronounced black stripes in evidence here were confusing. Could this be an introduced Hyla arborea population?  The distribution of the European or Common Tree Frog in Iberia is generally given as the north, north west and centre.

In fact, the juveniles of both species can have strong black markings, which shrink in adult Stripeless Tree Frogs.  The Common Tree Frog is also fatter.

Feet tucked out of sight, they were clinging to stems and leaves, smooth, pea-green mounds.  Unlike the Water frogs, which come in an infinite variety of green-brown combinations, Tree Frogs are quite uniformly coloured  (though a rare blue morph crops up).  The main variation is their size.

tree-frog-sitting-on-top-of-another

They’re inscrutable, with black stripes masking their eyes, like shadows permanently lying across them. The Water frogs leap almost as soon as you look at one, but these are easier to photograph, trusting in camouflage. When they do move, they reveal elastic-looking legs, and long toes tipped with round sticky pads.

feet-of-a-mediterranean-tree-frog

With Tree Frogs imprinted on my mind, I began spotting them everywhere.  Including one snoozing in the sun, camouflaged on a matching leaf, protruding right out of the park’s railings. You can see how the black stripe has faded away on this adult.

mediterranean-tree-frog-on-montjuic-barcelona

The season can betray them, though.

tree-frog-hyla-meridionalis-no-longer-camouflaged

Spring arrives for common toads

Written by Lucy Brzoska

There was something strange down there in the water.

I was walking the GR 5 from Sant Celoni to Montseny village, and had just spotted a grape hyacinth.  There’d been violets and speedwell along the way, but this was the first real spring bloom of the year.  I went up to have a look at the raceme of tightly clustered flowers, ranging from dark purple at the bottom with delicate white frills, to bright lilac on top, where they are sterile.

grape-hyacinth-muscari-neglectum

The grape hyacinth was growing just by a concrete irrigation pond, full of murky green water.  Something in the depths grabbed my attention.

common-toads-mating-underwater

It was a lump of toads, warty, saggy and stretched into a kind of ball.  I wasn’t even sure they were alive until a hind leg kicked and the ball drifted to a new spot.

After watching a while, I realised a gargantuan struggle was taking place.  At the bottom of the pile was an enormous mottled female, and clinging to her were at least four males, each a different colour – ranging from mustard yellow to dark grey.  Each was intent on levering off his rivals and manoeuvring into a better position.  Webbed feet were rammed into faces.  Heads were squashed under limbs. The shape of the ball evolved and floated about at the bottom of the pond.

common-toad-mating-ball

Intense competition like this can cause female toads to drown: they are bigger than the males but not strong enough to shrug off so many persistent suitors. It struck me as a system gone askew, with an inexplicable imbalance between the sexes.  But Mel on the forum explained that males are usually the first to arrive at the spawning sites, rearing to go.  So the first females to show up are outnumbered and put under enormous pressure.

An unattached male swam to the corner of the pond, iridescent orange-red eyes visible above the surface – a common toad’s most attractive feature – and began calling to summon more females.  It was an urgent but gentle sound – common toads don’t have vocal sacs -  similar to that of  a coot.

common-toad-bufo-bufo

At the other end of the pond were strings of small black eggs, freshly laid.

common-toad-eggs

It had turned into a spring walk.  Turo de l’Home’s snowcap was melting fast, and there was a roar in the beech woods, as fierce white torrents gushed downhill.  Butterflies were out in the sun: Brimstone, Cleopatra and Peacock.  At the end, when you have to run to catch the bus in Montseny village, there was a grassy bank covered in white violets.

white-violet

Sunday evening in sunny June

Written by Lucy Brzoska

Sometimes on a June evening Barcelona skies fall strangely silent because of an absence of swifts.  They go elsewhere for richer pickings, returning to the concrete sprawl at night.  Standing on the Collserola ridge at dusk, I watched hundreds pour down into the city.

I’d started walking late in the afternoon, skirting the small Vallvidrera reservoir, where families picnicked in the shade and dogs nosed among the algae, silencing the legions of frogs.  Climbing a steep path, where a meagre stream trickles down, I found Rampion Bellflowers and tiny tangy wild strawberries, which no one else had thought to pick.  Iberian Water Frogs (Pelophylax perezi) crouched invisibly in the grass around a small pool. Every time I moved, more would leap into the water and vanish, till it must’ve got quite crowded down there in the mud.

iberian-water-frog

Vallvidrera is posh, but some of the houses near the path were built when this was no man’s land, and the crowing of cockerels mingles with Golden oriole song.  A beautiful Comma butterfly (Polygonia c-album) was perched on a leaf, jagged as a jigsaw piece.  Perhaps it was the same one I’d seen a few days before, puddling on the wet stones, and giving me a glimpse of the neat white mark on its underwing to which it owes its name.

comma-butterfly-underwing-polygonia-c-album

As grass goes to seed, the slopes behind Sant Pere Martir are turning pale gold, the colour of summer.  The bright yellow flowers of broom have nearly gone, and now it’s time for Scabious (Scabiosa atropurpurea).   Its frothy purple-pink blooms are everywhere, on waist-high stems, leaves hardly to be seen, and usually with a butterfly attached.

marbled-white-melanargia-lachesis

Down in the valley bottom, rabbits rustled among the new crop of fennel that’s already taller than me.  An insistent screeching made me think a new exotic bird had arrived in Collserola.  Something large and yellow moved in a pine tree – a Golden oriole.  Until then I’d only known their catchy whistles, which starlings love to mimic.

Nearly at the top of the ridge, as the sun dropped lower, I stopped to admire the spectacular Illyrian thistles (Onopordum illyricum) that have shot up like spiny candelabra. Hummingbird Hawk moths were zipping among the electric purple flower heads. I’d seen a man come armed with gloves, cut some selected stems and strip them of thorns with a knife. If the Devil grows them in his garden – in Spanish they’re called Cardo del Demonio – it’s because both stems and flower heads are edible.

illyrian-thistles-onopordum-illyricum

illyrian-thistle-head-onopordum-illyricum

Beyond the thistles a flock of bee eaters were on a late foraging swoop. The swifts were beginning to return. I noticed a Woodchat shrike (Lanius senator) on a dried up branch of old broom, its chestnut crown lowered as it dealt with its prey. It flew off with something pale in its bill, having left an egg shell spiked on a twig.

It was delicious to lie down on the track and feel the day’s heat stored there, in contrast with the cool evening air, and listen to the sound of swifts searing past. A rabbit popped out of the grass, and promptly jumped back again. A boar emerged, huffed indignantly and kicked up the dust.

Darkness was falling and the swifts were still swarming along the length of the ridge.

Collserola: Guided Walks