Herons and Pelicans

The breeding season over for another year, by the end of August most herons have dispersed – though some will roost in the zoo during the winter. I found the plane trees deserted, with nursery activity reduced to the pines overlooking the pelicans, where young Cattle and Little egrets were still being fed. A handful of recently fledged herons also remained.

One grew tired of throat-wobbling and yakking, and crash-landed through the branches into the flamingo enclosure. The lion pen, fortunately, is quite far away. Dark and dishevelled, as if it had come through a chimney, it explored the area, not entirely sure where it was going. A more mature juvenile, sleek in morning suit-grey, exhibited the next stage of plumage in young herons.

The keeper arrived with a container of live goldfish, which he freed into the pelicans’ moat. It’s one way of stirring the hefty birds into action. They enthusiastically set about catching their lunch, casting their expandable bills sideways under water, like fishing nets. And there was plenty left for egrets and herons to practice their fishing skills too, deploying quite different strategies: the egrets would run after their prey, poised to change direction in an instant, while the herons relied on their long sinuous necks to snatch the fleeing fish. Owners of ornamental garden ponds would have had to look away.

As they live directly underneath the heronry, and share a fish diet, the pelicans are the captives most affected by its spectacular expansion. But although their placid existence has been disrupted, this year a pelican chick was successfully hatched, a rare occurrence in the zoo.

The one-footed Malibu stork that used to share the enclosure was immediately transferred elsewhere. A tough, powerfully-billed old warrior, it would brazen it out with the herons at their most competitive, while the pelicans, overwhelmed, huddled in a corner.

The baby pelican has grown into a vast fleecy lump that spends its life on a pedestal, being fed by doting parents. It appeared quite capable of looking after itself, lunging at one of the herons when it came too near. The startled heron waited till the chick had dozed off before approaching again, seeking out any forgotten fish.

Pelicans, herons and egrets, all were in moult, with feathers sticking out at odd angles, waiting to fall. The pelicans were like shabby old eiderdowns, shedding clouds of feathers. The plane tree leaves were also drifting down, and soon the empty nests will be visible again.

Citadel of Herons

Packed tight between the mountains and the sea, Barcelona is a noisy, densely populated city. Any visitor who climbs Montjuic or Tibidabo for an overall view will immediately be struck by the absence of green space. The nearest most people have to a garden is a few plant pots on a balcony. Yet in the heart of this intensely urban environment, there is a spectacular birding experience to be had.

I stood watching as the man swung his bucket, scattering silvery fish through the air and an extraordinary balletic display commenced. Tall gangling birds pranced across the grass, jostling in competition. Crests were cocked in excitement. Raucous cries rang out. Vast wings were spread like grey capes, as strong orange beaks grasped their catch. Long, sinuous necks bulged as it was swallowed.

The scene was Barcelona zoo, and the birds putting on the show were Grey herons (Ardea cinerea). Common enough species but rarely seen in such quantities and proximity. The zoo has over 200 of them, nesting high in the tree tops: the largest urban heronry in Europe.

The herons are sometimes mistaken by visitors as another exhibit, a decorative extra thrown in for the price of the ticket, like the peacocks who have the run of the place. But they are wild birds who have chosen to live in close proximity to man. When hunting for food outside the zoo grounds, they revert to extreme wariness, fleeing at the slightest human intrusion. Inside, other rules apply, providing a tremendous opportunity to observe them close up.

Walking through the zoo on a mild April morning, I spotted a heron in a palm tree snaking its neck to pluck some likely nesting material. Another had alighted in a plane tree to present a long twig to its mate. The pair raised their crests in greeting and exchanged raucous ruarks. Over by the penguin pool, herons kept guard, glassy eyes giving nothing away as they waited for feeding time.

Like Barcelona itself, the zoo can be noisy and crowded. A pretend train laden with visitors was winding along the paths, its bell ringing incessantly. The Cuban flamingos were in display mode, trumpeting in formation. Peacocks were screaming. Children on a school trip were shouting “Baloo! Baloo!” at a pair of slumbering Spanish brown bears. Adding to the congestion were lines of wide-eyed tiny-tots hanging onto long ropes. Dodging all these obstacles were the zoo staff, mounted on bikes.

The heronry adds a few more decibels to the general cacophony. As I approached the pelican and gorilla enclosures, a sign instructed me to look up. Overhead, in the towering plane trees, was the hub of the colony, where the large nests are packed close together and the whiff of a barnyard hangs in the air. Also emanating from above was a peculiar racket.

Scanning the boughs to find its source, I saw that several nests were already occupied by goggle-eyed spiky heads. The relentless nattering was the sound of ravenous heron chicks, leaning out precariously, wobbling their throats and demanding food.

Although still weeks away from acquiring the sleek elegance of their parents, some of the chicks were already quite grown, a sign of the colony’s success. Mild Barcelona weather and an ample food supply encourage early breeding. A record was set in 2007, after a particularly balmy winter, when the first chick hatched on January 8th. With such favourable conditions, some herons undertake two broods a year.

For more information I consulted Josep Garcia, an ornithologist who has studied Barcelona’s herons for more than 20 years. Spring is his busiest time as he monitors the entire heron population of Catalonia, wading unsteadily through lagoons, and climbing shaky ladders to peer at nests and ring chicks. In the zoo he has the amenities of a city at hand, and glides smoothly upwards in a tree pruner’s lift.

“You’ve visited the oldest Catalan heronry,” he explained, giving me a quick history lesson. “It was founded over thirty years ago in 1974 by captive birds with clipped wings. Two of their offspring were given their freedom, surprising everyone by returning to the zoo to breed.” Other herons passing on migration were attracted by the nests they spotted below.

“This year we might get as many as 130 nests,” says García, astounded by the prospect himself “Which is probably saturation point. The Barcelona heronry will be playing an important role in reinforcing or establishing new colonies as herons disperse. In the next few years, the Catalan colonies will acquire a great strategic importance as a nexus between heronries of southern France and the Mediterranean basin.” This has always been the role of Catalonia, to act as a bridge between Europe and Spain.

A benign climate is not the only advantage for Barcelona’s herons. In the centre of the city they have few predators to worry about. The principle danger for the chicks is falling from the nest or being pushed by a rival sibling. Conditions are much harsher in the Llobregat Delta by Barcelona airport, where herons nest among reeds. García explains that these “suffer intense predatory pressure from the introduced American mink and disturbance from boars [whose population has exploded in Catalonia in recent years]. Besides having to contend with the more “normal” predators such as the Marsh harrier and other raptors like the Bonelli’s eagle.”

Just as my neck was staring to ache from so much tree-top gazing, a keeper approached the pelican enclosure and the herons began parachuting down. I felt the turbulence generated by a 1.75 metre wingspan as one settled by my elbow. Ignoring me, it only had eyes for the bloke with the bucket.

The heron is an adaptable bird and some have learnt to take advantage of the zoo’s resources. As feeding time is short and competition fierce, their typical hunting techniques, based on patience and stealth, are of little use. Smaller and more nimble rivals, such as Yellow-legged gulls and Little egrets, send tension levels even higher.

A stressed heron is an electrical sight, as its most decorative feathers rise to the occasion. As they gathered nervously in the pelicans’ moat, long black head plumes were springing up like antennae and white neck fringes spiking out. When fish were flung their way, tugs of war erupted. One intrepid individual managed to poach an entire trout, which it slowly engulfed, like a python. The long neck, so useful for harpooning fish in shallow water, also came in handy when accepting an offering directly from the keeper’s hand, keeping him safely “at neck’s length”.

When nerves and feathers had subsided, the herons reverted to more archetypal behaviour, stalking the area with measured calm in search of forgotten morsels. Soon the grassy arena of earlier feeding battles was taken over by picnicking families.

I reflected on how much the flamboyant herons have transformed the zoo, by providing a counterbalance to the captive animals. They are now part of an increasingly valued biodiversity within its grounds. A wintering kingfisher has been known to slip into the aquarium through an open window. Unique in the city, a population of hedgehogs has been discovered, survivors of a pre-urban era. Six species of butterfly have been identified and three amphibians: the Iberian Water Frog, Midwife toad and Stripeless Treefrog. Adjacent to the Parc de la Ciutadella, (Citadel Park ) the zoo has an impressive collection of 96 species of trees. While it is acknowledged that modern zoos work hard at conservation on a global scale, linking up to form a worldwide network, they have another role to play: providing an oasis for local wildlife and encouraging visitors to appreciate it.

Later that week, when walking down Barcelona ‘s expensive central shopping boulevard, Passeig de Gracia, at twilight, I was thrilled to see the instantly recognisable silhouettes of two herons. Curved necks tucked in, broad wings steadily beating, they were heading home.

Facts:

  • The zoo heronry was founded in 1974.
  • Until 1992 it was the only stable heron breeding colony in Catalonia.
  • In 1997 the herons were joined by two other members of the ardeidae family: the Cattle egret and Little egret.
  • Landmark years in the colony’s growth were 1997, when 21 new pairs swelled the number of nests to 62, and 2003, when they reached 106.
  • The breeding period in the zoo can begin from the end of December until the end of July or beginning of August. This year the first egg hatched on February 14th. In 2007 it was as early as January 8th.
  • On average 4 eggs are laid per nest, and only 1 or 2 chicks survive.
  • Between 20 and 30% of the colony is resident. The others begin leaving in August, and return in February