SEO BIRDLIFE

Olivares Vivos successfully tests measures against the alarming decline of the European roller

The degradation and loss of habitat due to agricultural intensification or the installation of photovoltaic plants are pushing the European roller to the brink. To address this situation, through the LIFE Olivares Vivos+ project coordinated by SEO/BirdLife, a pilot study has been launched in semi-arid areas to establish a roadmap for the species’ recovery.

The action focused on installing 9 specially designed nest boxes for rollers in Campos de Uleila and Oro del Desierto (Almería), as well as Cortijo Torre Guájar (Granada), three demonstrative olive groves of LIFE Olivares Vivos+ located in semi-arid areas where adaptation of the model to climate change-sensitive scenarios is being studied. The results exceeded expectations from the outset, as roller breeding pairs quickly accepted the nest boxes, leading to a reproductive success with 13 chicks successfully fledging.

Nest box with eggs

Restoring the Species and Habitats

The European roller, recognizable for its striking blue plumage, is one of the most emblematic migratory birds of Andalusia, especially in arid regions. However, its presence in Spain and across Europe has suffered alarming declines in recent years. Therefore, under the LIFE Olivares Vivos+ project, SEO/BirdLife, the Estación Experimental de Zonas Áridas del CSIC (EEZA-CSIC), and the University of Jaén have developed a specific action with dual objectives: to promote the species’ reproduction within participating estates of Olivares Vivos, and on a larger scale, to use these locations as connectors for populations of rollers in the surrounding areas.

Nine nest boxes were installed with a new design specifically for rollers, 3 in each of the olive groves, following the same pattern. During the breeding season, 4 nest boxes were occupied. All of them were successful in breeding, resulting in the fledging of 13 chicks. In terms of location, Campos de Uleila was the most successful demonstrative estate, with all three nest boxes occupied and 10 chicks successfully fledged. At Cortijo Torre Guájar, a pair of rollers nested, successfully raising 3 chicks.

In addition to monitoring the nesting and chick development, scientific ringing was conducted using metal rings, and the three chicks at Cortijo Torre Guájar were also ringed with PVC rings for remote reading. This allows for individual identification and, with luck, tracking upon their return from African lands. Furthermore, blood samples were taken from the chicks to assess their health status regarding blood parasites and ectoparasites.

Post and nest box used in the pilot project

Francisco Valera, a scientist from EEZA-CSIC and a partner entity in the LIFE Olivares Vivos+ project, has been studying the European roller for decades and anticipates an increase in occupied nests in the upcoming breeding season. He highlights that the results have exceeded expectations, as birds typically take time to familiarize themselves with such support structures. Valera also notes that the reproductive success achieved with the nest boxes in this pilot study was higher compared to previously used ones.

A key factor contributing to this success could be attributed to the design of these nest boxes. Specifically, they were installed on 5-meter poles (with 1 meter buried underground as a foundation and 4 meters above ground), equipped with anti-predation measures and other features to mitigate adverse weather effects. These include roofs to protect against torrential rains or direct sunlight during peak temperatures.

European rollers currently face numerous threats, such as the lack of nesting sites, habitat destruction, and recent challenges like the 2023 drought followed by torrential rains, resulting in the loss of many broods. Moreover, given the increasing number of photovoltaic plant installations in the Campo de Tabernas area, deploying nest boxes with adapted designs could significantly mitigate the destruction of suitable nesting areas for these birds, whose habitats are becoming increasingly fragmented or disappearing altogether.

 

The European roller and the olive grove

The ecosystem services provided by nature to agrosystems are essential for creating resilient and truly sustainable crops. In this case, the relationship between European rollers and olive groves mainly focuses on pest control. Therefore, the presence of European rollers can play a significant role in the food chain, crucial for preventing the populations of invertebrate species from increasing excessively in spring. Additionally, it can act as a good bioindicator of an agricultural landscape that maintains fallow areas and open natural habitats (pastures).

In two of the estates where these nest boxes were installed, there were previous records of European rollers. One of them was Campos de Uleila, where a natural nest was also found when studying the locations for the nest boxes. The other box was installed at Cortijo Torre Guájar, and Francisco Martínez Raya, a farmer from the estate, highlights: “It was a very gratifying experience to see how such an emblematic bird of these lands found here a refuge and habitat that it considered suitable for breeding. Everyone at the estate has been eagerly anticipating, and we know they have visited our orchard to hunt insects like tiger spiders,” says Martínez Raya.

Francisco Martínez Raya, together with his two nieces

Along with the technicians from Olivares Vivos, a monitoring was conducted on the rollers that were installed in the nest box on the estate, and once the chicks reached the appropriate age, they were ringed. Reflecting on this day, Martínez Raya elaborates: “It was the icing on the cake of all the work we were doing with the youngest members of the family. We had already been teaching them to care for and protect biodiversity and the environment, but on this day they could see for themselves the result of it all: three chicks of a species endangered by habitat loss were born on our estate and shortly after, they flew. It is essential that these kinds of actions are made known to young people because they are the ones who will have to continue the task in the future.”

At the same time, José Eugenio Gutiérrez, director of the LIFE Olivares Vivos+ project, highlights the demonstrative value of this pilot experience. “One of the most notable contributions of Olivares Vivos is that beyond just restoring biodiversity in agricultural fields, we are learning a lot about how to do it with the greatest effectiveness and the best cost/benefit ratio. It’s not just about putting nest boxes, but about how to do it: how to design them and where to place them so that, beyond being occupied, they help increase the breeding success of species as valuable for conservation as the roller.”

LIFE Olivares Vivos+

Since 2015, with the funding of two LIFE projects, Olivares Vivos has developed and implemented this innovative olive farming model born from consensus among farmers, scientists, and conservationists. Now, through the LIFE Olivares Vivos+ (2021-2026), efforts are underway to accelerate the dissemination of this model across the main European olive-growing regions, expand it to other products like table olives, and transfer it to other crops; the latter is currently being achieved through the Secanos Vivos project. There’s also work ongoing to adapt the model to the cooperative sector through the Cooperalive Operational Group, and to study the effect of herbaceous cover crops in olive groves with the Coverolive Operational Group.

LIFE Olivares Vivos+ is developed by SEO/BirdLife as the coordinating partner, along with the Provincial Government of Jaén, University of Jaén, Estación Experimental de Zonas Áridas (EEZA-CSIC), University of Évora, agricultural and forestry cooperative DREAm-Italia, Organización Agrícola Helena, and Juan Vilar Strategic Consultants. The project is funded by the European Commission’s LIFE program, with co-financing from the Provincial Government of Jaén, the Ministry of Agriculture, Livestock, Fisheries, and Sustainable Development of the Andalusian Regional Government, and financial support from the Spanish Olive Oil Interprofessional, the Regional Government of Castilla-La Mancha, and Caja Rural de Jaén.

 

**Author of the cover photography: Manuel Gómez

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CONÓCENOS

La Sociedad Española de Ornitología es la entidad conservacionista decana de España. Desde 1954, sigue teniendo como misión conservar la biodiversidad, con la participación e implicación de la sociedad, siempre con las aves como bandera.

SEO/BirdLife es la representante en España de BirdLife International, una federación que agrupa a las asociaciones dedicadas a la conservación de las aves y sus hábitats en todo el mundo, con representación en más de 100 países y más de 13 millones de socios.

Es el socio coordinador del LIFE Olivares Vivos+.