Millions of birds leave Europe each year at the end of the breeding season and migrate to Africa in search of warmer places to overwinter. The osprey is one of those migratory species that does not hesitate to leave its birthplace, mainly around lakes and rivers in the north of the continent, to survive. The Langue de Barbarie (PNLB) National Park in northern Senegal in the Saint Louis region is home to more than 200 specimens between October and April, the highest non-breeding season concentration of this bird documented in Africa to the Spanish biologists Rafa Benjumea and Blanca Pérez, which they have been examining with local experts since 2015.
An osprey in Langue de Barbarie National Park (PNLB) in northern Senegal.
“The importance of this bird of prey, distributed worldwide but rare in Spain, is that it feeds exclusively on fish, so its disappearance or reduction in specimens would cause an imbalance in the ecosystem that is difficult to replace,” explains Benjumea. , specialist in animal migration. Biologists explain that it is an “umbrella species”, that is, that it is part of a group whose protection also implies the indirect conservation of other animals in the same habitat.
It is estimated that half of the birds that make the route each season die en route
In the first year that Pérez and Benjumea traveled to Senegal, they did so with the aim of assisting in the development of a strategic management plan for the national park and training agents to conduct censuses. They soon recognized the extraordinary concentration of ospreys and the importance of knowing their structure and behavior in the area. “A lot of effort is being put into conserving it in Europe, but there is very little data in Africa,” the biologist clarifies. Since then, together with the staff of the PNLB, both have focused on documenting this population. In 2023, the results of the first four years of the study, scientifically supported by the University of Málaga and the Joint Institute for Biodiversity Research CSIC of the University of Oviedo, will be published.
In mid-January, the team managed to ring and fire with a GPS system to two adult ospreys. “Usually in Europe, they are marked at birth in the nest, and since the device lasts about three years, the movements of this first phase of the animal’s life are known in detail,” Benjumea specifies.
Spanish biologist Rafa Benjumea shows a Senegal worker how to ring an osprey. Blanca Perez
To do this, they devised various trapping systems, spent nights outdoors and waited for hours for one of these birds of prey to step into the trap so they could place what they called the “small backpack”, a device containing a transmitter and a small solar panel. The effort was rewarded. The first was a female without a band and therefore without information on origin and date of birth. They named it Tougou, in reference to the Belgian association Project Tougoupeul, the main funder of the mission.
The importance of this bird of prey, widespread throughout the world but rare in Spain, is that it feeds exclusively on fish, so its disappearance or reduction in specimens would cause an imbalance in the ecosystem that would be difficult to replace.
Rafa Benjumea, biologist
“With this we will study habitat use during the non-breeding season in Senegal and also the migration route to its breeding grounds in Europe. With this important information, we will increase the knowledge of the species for its own conservation and for the protection of wetlands in Africa,” reveals Pérez, explaining that the Senegalese park they work in, the PNLB, is part of the Unesco Biosphere Reserve and included is the so-called Ramsar List of Wetlands of Great Importance, named after the Iranian city where this protection agreement was signed. The last census carried out on January 15 saw 152 ospreys counted in one morning, representing more than 1% of the population born in Europe (in 2021 the existence of between 9,600 and 13,600 breeding pairs was estimated), explains the park curator, Captain Nicolas Gomis.
Migrations, a history of connections between scholars
Migratory birds bring together disparate countries, cultures and explorers on their annual adventure, who must work together along the entire route with the common goal of protecting them on their journey. Evidence of this is the story of Gallo, the second osprey specimen analyzed on this mission.
It was known from the metal ring he wore that he was born in Finland, so Benjumea spoke to colleagues in the Scandinavian country to contact the wrestler, who revealed it was a man born in 2019, specifically in the city of Kuhmalahti. , in the south of this country. “Most of those born in this region transit Georgia and often emigrate to East Africa: Gallo [que ha migrado al oeste del continente] It confirms that nature is not always what we predict,” says the Sevillian scientist.
A female Osprey soars in the air in Senegal.
Like Tougou, he was also equipped with a GPS device on his back that regularly generates information. Already in the first days of the tracking, in which data on the temperature, altitude, speed and location of the bird is offered every 20 minutes, the team made new discoveries, such as that the eagles flew over more territory than expected and happened moments that are as important as getting a good night’s sleep outside the park. “This supports the need to protect not only the reserves but also the surrounding communities,” explains Pérez.
In addition to the usual risks that threaten the migratory routes, such as coastal construction, wetland drying, wind farms and deforestation, when these species reach this part of Africa they must also face other threats such as desert storms or reservoirs, for example Diama on the Senegal River, which reduce the food supply. It is estimated that half of the birds that make the route each season die en route.
For Moussa Niang, PNLB ecoguard, these collaborations with biologists like Pérez and Benjumea are crucial for the professionalization of the sector in Senegal, which does not yet have its own ringing system. “I managed to validate my knowledge through the practices I do with foreign scientists and I managed to be the first qualified bander in the country for the monitoring of five species,” he confirms.
Follow PLANETA FUTURO on TwitterFacebook and Instagram and subscribe to our “Newsletter” here.