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Once a common sight along the Danube or Rhône basins, and with breeding sites in rocky areas across Germany, Spain, Italy and Switzerland, as well as Turkey and Syria, the northern bald ibis has since disappeared in the wild, with the exception of its last stronghold in Morocco. The Centro de Conservación de la Biodiversidad Zoobotánico de Jerez-Alberto Durán – a public institution under Jerez City Council – has successfully reintroduced the species in the La Janda district (Cádiz), and is now working towards the re-establishment of a migratory population between Spain and Austria. These signal achievements have won the organization the Award for Biodiversity Conservation in Spain.
The northern bald or hermit ibis, a blackish bird with a long curved beak and the characteristic head that gives it its name, has gone from being found throughout North Africa, the Middle East, Southern Europe – including Spain – and Central Europe to living in the wild exclusively in Morocco, which is home to some 700 sedentary individuals, split between the Souss-Massa and Tamri national parks.
“The northern bald ibis is a bird that lives in groups, spends a lot of time on the ground and feeds mainly on insects, which it extracts with its long beak. For this reason, its ideal habitat is grassland,” explains Miguel Ángel Quevedo, one of the vets in charge of the Eremita Project at the Jerez Zoological and Botanical Gardens (ZBJ). “In the past fifty years, its world population has slumped by 90 percent as a consequence of hunting, pesticides and land-use changes, which have gradually turned pastures into crop fields.”
This startling decline was a wake-up call for international conservationist organizations. At a meeting of experts held in Morocco in 1999, under the auspices of the United Nations Environment Programme, it was decided to set up the International Advisory Group for the Northern Bald Ibis (IAGNBI). The first step, the experts concluded, was to investigate and identify the best release methods to obtain sedentary, stable and self-sufficient populations in areas suitable for the species to thrive. At the same time, in the 1990s, the European Association of Zoos and Aquaria (EAZA) launched an ex situ breeding program; in view of “the paradox,” as Quevedo describes it, “of having between 1,000 and 1,500 northern bald ibises in zoos across the continent, while the bird was going extinct in the wild.” The ZBJ joined this effort by creating a breeding colony that, when the time came, could become a springboard for the species’ reintroduction into the wild.
The final impetus came in 2003, when an IAGNBI meeting in Innsbruck proposed southern Spain as a suitable test ground, given that the species nests on coastal and inland cliffs. And in 2004, another expert group meeting in Madrid to discuss the Northern Bald Ibis Action Plan marked the definitive launch of the Eremita Project.
The ZBJ settled on the La Janda district in the province of Cádiz. Under a partnership agreement with the Spanish Ministry of Defence, an aviary was installed at one end of the Retín military zone, near Zahara de los Atunes, while the Regional Government of Andalucía co-financed the study of release methods, with scientific input from the Estación Biológica de Doñana (CSIC).
The Jerez institution – which in the course of a decade had established a captive breeding colony that was genetically diverse – set the process in motion following an environmental impact assessment. “The individuals involved with the captive breeding wore black t-shirts and helmets in the form of the northern bald ibis. This meant the chicks would imprint on them when dressed this way but would not recognize them in other clothes,” Quevedo explains. “That was important because, once in the wild, we didn’t want the birds approaching any human they crossed paths with, but we did want them to follow their disguised caretakers and expand through the area when the aviary was opened.” The birds were released between 4 and 8 months after their arrival at the Retín aviary, achieving a sharp reduction in juvenile mortality. In addition, a number of them were fitted with radio transmitters for monitoring in the wild. Starting in 2004, the ZBJ raised, released and monitored around 30 chicks a year, an effort that four years later would produce a major and consequential milestone: the first reproduction in the wild of birds born in captivity.
In 2012, the project entered its next phase. With the collaboration of EAZA, more than thirty zoos in Austria, the Czech Republic, France, Germany, Hungary, Italy, the Netherlands, Switzerland, the United Kingdom and the United States began sending juveniles to the Eremita Project. “This meant we could introduce around 60 chicks a year, successfully integrating ZBJ and European birds,” says Mariano Cuadrado, a conservation biologist and another of the project’s leaders. The integration process was helped along by the 2018 construction of a new acclimatization and release aviary in the San Ambrosio zone between Vejer and Barbate. “This aviary – Miguel Ángel Quevedo points out – is sited in one of the ibis’s foraging areas, so, from the very first moment, captive individuals have visual and acoustic contact with the birds in the wild, which at times even sleep on top of the cage.”
“Since 2014 we have seen between 35 and 55 chicks annually born in the wild,” says Mariano Cuadrado, “so we already have a population that is stable, and possibly – we are evaluating it – self-sustaining, with more individuals born than dying.” To confirm this, he adds, “we have stopped introducing captive-bred chicks.” The number of breeding pairs and wild-born chicks is growing every year, with 32 nests spread over 3 colonies recorded in 2024, producing 64 hatchlings.
Parallel to the Eremita Project, a group of Austrian experts known as the Waldrapp Team were working on the ibis’s reintroduction. Their goal was to establish a migratory population between Austria and the Italian region of Tuscany by means of human-led migration to their winter homes, with the birds following an ultralight aircraft. The idea was that when spring came they would return from there to their home breeding grounds. However the initiative suffered a number of setbacks, which could not be satisfactorily overcome.
Then in 2022, a captive-born bird (a male named Ingrid) released in Austria by the Waldrapp Team appeared in the town of Cártama (Málaga), after journeying more than 2,000 km. Inspired by this success, the proposal was made to merge the two projects, switching the birds’ destination from northern Italy to southern Spain. In August 2023, the first guided migration took place from Austria to Cádiz; a long flight of some 2,200 km taking in over 20 stages. The birds arrived in San Ambrosio in October 2023. “The La Janda population is sedentary, but there are already two individuals that have made the journey there and back, so it looks as if we could re-establish a migratory population,” enthuses Quevedo, unable to hide his excitement.
The reintroduction of the ibis is, says Cuadrado, “the culmination of years of work with endangered Iberian species: the Iberian lynx, the spoonbill, the Egyptian vulture, the bearded vulture, the marbled duck and the lesser kestrel, among others.” Maher Mahjoub, head of the Centre for Mediterranean Cooperation of the International Union for Conservation of Nature cites these and other successes when hailing the ZBJ as “an international reference” in breeding projects for endangered species. For as Quevedo says, “our interest lies not in exhibiting animals, but in their conservation.”
Photo credit: Zoobotánico de Jerez