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GPS and genetic monitoring: Evaluating the connectivity of Bearded Vulture populations between different massifs in France

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Bearded Vulture in flight (c) Bruno Berthemy

The LIFE GYPCONNECT project aims to connect the population of Bearded Vultures in the Alps and the Pyrenees, marking the first step towards recovering the species’ European metapopulation. To assess the connectivity between the Pyrenees, the Massif Central and the Alps, we used two methods — GPS data and genetic information. Additionally, the observation of ringed birds or the marking of feathers by discolouration can provide information in the absence of GPS data.

GPS data analysis and results

To evaluate the connectivity between populations, we analyzed the GPS data from a total of 118 Bearded Vultures. Out of these, 48 were tagged between 2010 and 2020 in the LIFE GYPCONNECT project area — 14 in Vercors, 22 in the Massif Central, 11 in the Baronnies and one bird in the Pyrenees. In the Alps, 70 birds were equipped between 2004 and 2020. The different partners of the International Bearded Vulture Monitoring Network (IBM), coordinated by the VCF, provided the GPS data for birds in the Alps.

Based on GPS data, a total of 10 birds moved from one massif to another. A distinction is made among birds’ movement between the Alps and the Massif Central and between the Massif Central and the Pyrenees and vice versa. According to the GPS data, no direct exchange between the Pyrenees and the Alps has been established. As it is shown in the map, no green points are visible in the Alps, and no yellow or blue points are visible in the Pyrenees.

The GPS data of all birds monitored between 2004 and 2020 in the Alps, the Massif Central and the Pyrenees is organized according to the release site or occupied territory. The birds released in the three release sites of LIFE GYPCONNECT are indicated in light blue (Vercors), dark blue (Baronnies) and purple (Massif Central). Furthermore, dark blue barriers separate the mountain massifs. A fix every 2-hour is illustrated.

The analysis shows that two birds have left the release sites in the Pre-Alps (Baronnies and Vercors):

  • ProNatura released in 2017 in the Baronnies flew to the Massif Central and unfortunately died there.
  • Angelo, released in 2012 in the Vercors, flew to the Massif Central, then returned to the Southern Alps and finally to the Central Alps where he unfortunately died.

The number of birds leaving their territory is higher in the Massif Central than in the Pre-Alps and the Alps. One factor influencing this number is the size of the massif and the release sites’ position. The Massif Central is a small area and birds that fly a certain distance will therefore quickly leave the massif. The Vercors and the Baronnies are at the western end of the Alps, so when the birds fly west, they quickly find themselves outside the Alps. As for the birds released in the Alps, large movements inside the massif are also possible. In total, six birds released in the Massif Central left the massif and moved to another massif. Lausa, released in 2019, unfortunately, died in the Alps. Adonis, Calandretto and Cévennes left but returned to the Massif Central.

Genetic monitoring analysis and results

Genetic monitoring is based on 742 genotypes of captive and released birds, and wild birds from the Alps, the Pyrenees and Corsica, based on the database of Pro Bartgeier. Feathers collected under the nesting sites by local partners allow the identification of nesting birds. On the territory of Bonnette, in the Mercantour National Park in France, feathers found in 2016 showed a new genotype GT0150, belonging to a male. It was not possible to determine this bird’s parents — a later comparison with genotypes from different populations allowed to place this genotype within the Pyrenean population. The first feathers were found in 2016 during its breeding, and other feathers were found in 2017 and 2018. It is still unknown which path and at what age the bird dispersed from the Pyrenees to the Alps.

Several birds moved between the different massifs, but only in two cases, breeding outside the original territory (dispersal from the site of origin or hatching) was observed (Basalte and GT0150). Basalt (Massif Central 2012) breeds in the Malaval territory in the French Alps. GT0150 has been confirmed several times in the Bonnette territory between 2016 and 2018. Unfortunately, it is not known whether Cardabelle (Massif Central, 2012) breeds in the Pyrenees. The last observation of Cardabelle dates back to May 2016 in Aragon. Ultimately, only natal dispersal events will lead to a necessary gene flow between the population. 

The movements analyzed in this report are very important, and the reproduction of GT0150 from the Pyrenees to the Alps certainly shows that a first genetic exchange has taken place.

The analysis was conducted by Franziska Loercher, VCF’s Scientific and conservation coordinator, within the LIFE GYPCONNECT project, and the report summary was first published in the eighth edition of La Plume du LIFE.

LIFE GYPCONNECT

Led by the League pour la Protection des Oiseaux (LPO), the LIFE GYPCONNECT project aims to establish a breeding population of Bearded Vultures in the Massif Central and Department of the Drôme. Releasing captive-bred Bearded Vultures into the wild at sites such as the Parc Naturel Régional des Grands Causses,  Parc Naturel Régional des Baronnies Provençales and Parc Naturel Régional du Vercors will create a core population that will connect the two populations of the species in the Alps and Pyrenees. To facilitate movements between the new population and the Alpine and Pyrenean populations the LIFE GYPCONNECT team is creating a network of supplementary feeding stations, and tackling threats such as poisoning, and collision and electrocution with the electricity infrastructure.

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