The aviary for the soft release of Cinereous Vultures aims to strengthen the fragile Douro Internacional’s breeding colony
On 21 May 2024, on Europe’s Natura 2000 Day, an acclimatisation aviary for Cinereous Vultures (Aegypius monachus) was inaugurated in the Douro Internacional Natural Park in Portugal, as part of the LIFE Aegypius Return project. Four juvenile Cinereous Vultures are already in the acclimatisation aviary and will be released in the autumn.
Acclimatisation with a view
The acclimatisation aviary was built at Fornos, in the municipality of Freixo de Espada à Cinta, within the Douro Internacional Natural Park, in northern Portugal, and consists of a large cage (18 metres long, nine metres wide and six to eight metres high) adjacent to a supplementary feeding station for scavenging birds.
The NGO Palombar – the LIFE Aegypius Return partner responsible for building and managing the aviary – planned the facilities in detail to ensure the birds’ well-being and socialisation. Inside the aviary, the vultures have perches, ramps, branches and even a bathtub – all with a breathtaking view over the Douro river canyon. Outside, in front of the aviary, there is a fenced feeding station of around 2 hectares (work carried out by Associação Transumância e Natureza), where food is placed to mimic the availability of carcasses in the wild (Cinereous Vultures are obligatory scavengers). Thus, from inside the aviary, the Cinereous Vultures will be able to observe and interact with their counterparts and other species, socialising and learning natural behaviours such as feeding and identifying danger.
The Douro Internacional was the area selected for the acclimatisation of Cinereous Vultures, within the LIFE Aegypius Return project, as it is home to the smallest, most fragile and isolated colony in Portugal. In 2022 only two breeding pairs were known in the region; in 2024 this increased to seven pairs – four on the Portuguese side and three more on the Spanish side – but the isolation of the colony makes natural expansion difficult.
Pioneering conservation technique in Portugal
Acclimatisation is a period during which the birds get used to a particular region, in this case, the Douro Internacional. It is part of a process generally known as soft release, which has not yet been applied in Portugal with any species.
Soft release programmes have been applied in various regions of Europe and have been described and tested with various species of vultures. Compared to other techniques used in conservation programmes, soft release allows birds to remain loyal to the release area and is a recommended procedure for accelerating settlement, preventing dispersion from the release area, and increasing the viability of a population.
In LIFE Aegypius Return, the Cinereous Vultures that enter acclimatisation will be juvenile birds originating exclusively from wildlife rehabilitation centres in Portugal. In other words, they are birds that were born and raised in the wild, but due to injury or weakness had to enter a wildlife rehabilitation centre, without having established breeding territory yet (which in Cinereous Vultures only happens at five or six years of age). After their rehabilitation, instead of being returned directly to the wild, they will be sent for acclimatisation for between five and nine months. After this period, they will be released by opening the cage, and it is hoped that they will remain in the region of the Douro International Nature Park and establish their nesting territory there.
Four Cinereous Vultures await freedom
The acclimatisation facilities were inaugurated with four Cinereous Vultures, three females and one male. These vultures were rescued in Évora, Monte Junto and Belmonte, and then transferred to the Centre for the Study and Recovery of Wild Animals (CERAS), located in Castelo Branco and managed by Quercus, where they have been recovering. The introduction of the vultures into the cage was monitored by teams of veterinarians from CERAS and the Centre for the Recovery of Wild Animals at the Veterinary Hospital of the University of Trás-os-Montes and Alto Douro (CRAS/HV-UTAD). The birds were ringed, biological samples were collected and, before they are returned to the wild – which is planned for next autumn – they will be fitted with GPS transmitters.
The birds are now being monitored via the video surveillance system installed in the acclimatisation aviary. In the event of an emergency, CRAS/HV-UTAD veterinarians can quickly rush to the scene and provide assistance, using a small infirmary attached to the aviary.
By 2027, the LIFE Aegypius Return project plans to return 20 Cinereous Vultures to the wild through soft release. Naturally, all these procedures require a permit from the national nature conservation authority, the ICNF – Instituto da Conservação da Natureza e das Florestas, which is following the initiative.
LIFE Aegypius Return partners would like to thank all the people and organisations involved in the construction, management and inauguration of the acclimatisation aviary – a central milestone for the success of the project and, consequently, for the consolidation of Cinereous Vulture populations in Portugal.
LIFE Aegypius Return
The LIFE Aegypius Return project is co-financed by the European Union’s LIFE programme. Its success depends on the involvement of all the relevant stakeholders, and the collaboration of the partners, the Vulture Conservation Foundation (VCF), the coordinating beneficiary, and the local partners Palombar – Conservação da Natureza e do Património Rural, Herdade da Contenda, Sociedade Portuguesa para o Estudo das Aves, Liga para a Protecção da Natureza, Associação Transumância e Natureza, Fundación Naturaleza y Hombre, Guarda Nacional Republicana and Associação Nacional de Proprietários Rurais Gestão Cinegética e Biodiversidade.
